diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/buffer.go b/demo_test/vendor/github.com/golang/protobuf/proto/buffer.go
new file mode 100644
index 0000000..62df7e3
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/buffer.go
@@ -0,0 +1,324 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	"errors"
+	"fmt"
+
+	"google.golang.org/protobuf/encoding/prototext"
+	"google.golang.org/protobuf/encoding/protowire"
+	"google.golang.org/protobuf/runtime/protoimpl"
+)
+
+const (
+	WireVarint     = 0
+	WireFixed32    = 5
+	WireFixed64    = 1
+	WireBytes      = 2
+	WireStartGroup = 3
+	WireEndGroup   = 4
+)
+
+// EncodeVarint returns the varint encoded bytes of v.
+func EncodeVarint(v uint64) []byte {
+	return protowire.AppendVarint(nil, v)
+}
+
+// SizeVarint returns the length of the varint encoded bytes of v.
+// This is equal to len(EncodeVarint(v)).
+func SizeVarint(v uint64) int {
+	return protowire.SizeVarint(v)
+}
+
+// DecodeVarint parses a varint encoded integer from b, returning the
+// integer value and the length of the varint.
+// It returns (0, 0) if there is a parse error.
+func DecodeVarint(b []byte) (uint64, int) {
+	v, n := protowire.ConsumeVarint(b)
+	if n < 0 {
+		return 0, 0
+	}
+	return v, n
+}
+
+// Buffer is a buffer for encoding and decoding the protobuf wire format.
+// It may be reused between invocations to reduce memory usage.
+type Buffer struct {
+	buf           []byte
+	idx           int
+	deterministic bool
+}
+
+// NewBuffer allocates a new Buffer initialized with buf,
+// where the contents of buf are considered the unread portion of the buffer.
+func NewBuffer(buf []byte) *Buffer {
+	return &Buffer{buf: buf}
+}
+
+// SetDeterministic specifies whether to use deterministic serialization.
+//
+// Deterministic serialization guarantees that for a given binary, equal
+// messages will always be serialized to the same bytes. This implies:
+//
+//   - Repeated serialization of a message will return the same bytes.
+//   - Different processes of the same binary (which may be executing on
+//     different machines) will serialize equal messages to the same bytes.
+//
+// Note that the deterministic serialization is NOT canonical across
+// languages. It is not guaranteed to remain stable over time. It is unstable
+// across different builds with schema changes due to unknown fields.
+// Users who need canonical serialization (e.g., persistent storage in a
+// canonical form, fingerprinting, etc.) should define their own
+// canonicalization specification and implement their own serializer rather
+// than relying on this API.
+//
+// If deterministic serialization is requested, map entries will be sorted
+// by keys in lexographical order. This is an implementation detail and
+// subject to change.
+func (b *Buffer) SetDeterministic(deterministic bool) {
+	b.deterministic = deterministic
+}
+
+// SetBuf sets buf as the internal buffer,
+// where the contents of buf are considered the unread portion of the buffer.
+func (b *Buffer) SetBuf(buf []byte) {
+	b.buf = buf
+	b.idx = 0
+}
+
+// Reset clears the internal buffer of all written and unread data.
+func (b *Buffer) Reset() {
+	b.buf = b.buf[:0]
+	b.idx = 0
+}
+
+// Bytes returns the internal buffer.
+func (b *Buffer) Bytes() []byte {
+	return b.buf
+}
+
+// Unread returns the unread portion of the buffer.
+func (b *Buffer) Unread() []byte {
+	return b.buf[b.idx:]
+}
+
+// Marshal appends the wire-format encoding of m to the buffer.
+func (b *Buffer) Marshal(m Message) error {
+	var err error
+	b.buf, err = marshalAppend(b.buf, m, b.deterministic)
+	return err
+}
+
+// Unmarshal parses the wire-format message in the buffer and places the decoded results in m.
+//
+// Unlike proto.Unmarshal, this does not reset the message before starting to unmarshal.
+func (b *Buffer) Unmarshal(m Message) error {
+	err := UnmarshalMerge(b.Unread(), m)
+	b.idx = len(b.buf)
+	return err
+}
+
+type unknownFields struct{ XXX_unrecognized protoimpl.UnknownFields }
+
+func (m *unknownFields) String() string { panic("not implemented") }
+func (m *unknownFields) Reset()         { panic("not implemented") }
+func (m *unknownFields) ProtoMessage()  { panic("not implemented") }
+
+// DebugPrint dumps the encoded bytes of b with a header and footer including s
+// to stdout. This is only intended for debugging.
+func (*Buffer) DebugPrint(s string, b []byte) {
+	m := MessageReflect(new(unknownFields))
+	m.SetUnknown(b)
+	b, _ = prototext.MarshalOptions{AllowPartial: true, Indent: "\t"}.Marshal(m.Interface())
+	fmt.Printf("==== %s ====\n%s==== %s ====\n", s, b, s)
+}
+
+// EncodeVarint appends an unsigned varint encoding to the buffer.
+func (b *Buffer) EncodeVarint(v uint64) error {
+	b.buf = protowire.AppendVarint(b.buf, v)
+	return nil
+}
+
+// EncodeZigzag32 appends a 32-bit zig-zag varint encoding to the buffer.
+func (b *Buffer) EncodeZigzag32(v uint64) error {
+	return b.EncodeVarint(uint64((uint32(v) << 1) ^ uint32((int32(v) >> 31))))
+}
+
+// EncodeZigzag64 appends a 64-bit zig-zag varint encoding to the buffer.
+func (b *Buffer) EncodeZigzag64(v uint64) error {
+	return b.EncodeVarint(uint64((uint64(v) << 1) ^ uint64((int64(v) >> 63))))
+}
+
+// EncodeFixed32 appends a 32-bit little-endian integer to the buffer.
+func (b *Buffer) EncodeFixed32(v uint64) error {
+	b.buf = protowire.AppendFixed32(b.buf, uint32(v))
+	return nil
+}
+
+// EncodeFixed64 appends a 64-bit little-endian integer to the buffer.
+func (b *Buffer) EncodeFixed64(v uint64) error {
+	b.buf = protowire.AppendFixed64(b.buf, uint64(v))
+	return nil
+}
+
+// EncodeRawBytes appends a length-prefixed raw bytes to the buffer.
+func (b *Buffer) EncodeRawBytes(v []byte) error {
+	b.buf = protowire.AppendBytes(b.buf, v)
+	return nil
+}
+
+// EncodeStringBytes appends a length-prefixed raw bytes to the buffer.
+// It does not validate whether v contains valid UTF-8.
+func (b *Buffer) EncodeStringBytes(v string) error {
+	b.buf = protowire.AppendString(b.buf, v)
+	return nil
+}
+
+// EncodeMessage appends a length-prefixed encoded message to the buffer.
+func (b *Buffer) EncodeMessage(m Message) error {
+	var err error
+	b.buf = protowire.AppendVarint(b.buf, uint64(Size(m)))
+	b.buf, err = marshalAppend(b.buf, m, b.deterministic)
+	return err
+}
+
+// DecodeVarint consumes an encoded unsigned varint from the buffer.
+func (b *Buffer) DecodeVarint() (uint64, error) {
+	v, n := protowire.ConsumeVarint(b.buf[b.idx:])
+	if n < 0 {
+		return 0, protowire.ParseError(n)
+	}
+	b.idx += n
+	return uint64(v), nil
+}
+
+// DecodeZigzag32 consumes an encoded 32-bit zig-zag varint from the buffer.
+func (b *Buffer) DecodeZigzag32() (uint64, error) {
+	v, err := b.DecodeVarint()
+	if err != nil {
+		return 0, err
+	}
+	return uint64((uint32(v) >> 1) ^ uint32((int32(v&1)<<31)>>31)), nil
+}
+
+// DecodeZigzag64 consumes an encoded 64-bit zig-zag varint from the buffer.
+func (b *Buffer) DecodeZigzag64() (uint64, error) {
+	v, err := b.DecodeVarint()
+	if err != nil {
+		return 0, err
+	}
+	return uint64((uint64(v) >> 1) ^ uint64((int64(v&1)<<63)>>63)), nil
+}
+
+// DecodeFixed32 consumes a 32-bit little-endian integer from the buffer.
+func (b *Buffer) DecodeFixed32() (uint64, error) {
+	v, n := protowire.ConsumeFixed32(b.buf[b.idx:])
+	if n < 0 {
+		return 0, protowire.ParseError(n)
+	}
+	b.idx += n
+	return uint64(v), nil
+}
+
+// DecodeFixed64 consumes a 64-bit little-endian integer from the buffer.
+func (b *Buffer) DecodeFixed64() (uint64, error) {
+	v, n := protowire.ConsumeFixed64(b.buf[b.idx:])
+	if n < 0 {
+		return 0, protowire.ParseError(n)
+	}
+	b.idx += n
+	return uint64(v), nil
+}
+
+// DecodeRawBytes consumes a length-prefixed raw bytes from the buffer.
+// If alloc is specified, it returns a copy the raw bytes
+// rather than a sub-slice of the buffer.
+func (b *Buffer) DecodeRawBytes(alloc bool) ([]byte, error) {
+	v, n := protowire.ConsumeBytes(b.buf[b.idx:])
+	if n < 0 {
+		return nil, protowire.ParseError(n)
+	}
+	b.idx += n
+	if alloc {
+		v = append([]byte(nil), v...)
+	}
+	return v, nil
+}
+
+// DecodeStringBytes consumes a length-prefixed raw bytes from the buffer.
+// It does not validate whether the raw bytes contain valid UTF-8.
+func (b *Buffer) DecodeStringBytes() (string, error) {
+	v, n := protowire.ConsumeString(b.buf[b.idx:])
+	if n < 0 {
+		return "", protowire.ParseError(n)
+	}
+	b.idx += n
+	return v, nil
+}
+
+// DecodeMessage consumes a length-prefixed message from the buffer.
+// It does not reset m.
+func (b *Buffer) DecodeMessage(m Message) error {
+	v, err := b.DecodeRawBytes(false)
+	if err != nil {
+		return err
+	}
+	return UnmarshalMerge(v, m)
+}
+
+// DecodeGroup consumes a message group from the buffer.
+// It assumes that the start group marker has already been consumed and
+// consumes all bytes until (and including the end group marker).
+// It does not reset m.
+func (b *Buffer) DecodeGroup(m Message) error {
+	v, n, err := consumeGroup(b.buf[b.idx:])
+	if err != nil {
+		return err
+	}
+	b.idx += n
+	return UnmarshalMerge(v, m)
+}
+
+// consumeGroup parses b until it finds an end group marker, returning
+// the raw bytes of the message (excluding the end group marker) and the
+// the total length of the message (including the end group marker).
+func consumeGroup(b []byte) ([]byte, int, error) {
+	b0 := b
+	depth := 1 // assume this follows a start group marker
+	for {
+		_, wtyp, tagLen := protowire.ConsumeTag(b)
+		if tagLen < 0 {
+			return nil, 0, protowire.ParseError(tagLen)
+		}
+		b = b[tagLen:]
+
+		var valLen int
+		switch wtyp {
+		case protowire.VarintType:
+			_, valLen = protowire.ConsumeVarint(b)
+		case protowire.Fixed32Type:
+			_, valLen = protowire.ConsumeFixed32(b)
+		case protowire.Fixed64Type:
+			_, valLen = protowire.ConsumeFixed64(b)
+		case protowire.BytesType:
+			_, valLen = protowire.ConsumeBytes(b)
+		case protowire.StartGroupType:
+			depth++
+		case protowire.EndGroupType:
+			depth--
+		default:
+			return nil, 0, errors.New("proto: cannot parse reserved wire type")
+		}
+		if valLen < 0 {
+			return nil, 0, protowire.ParseError(valLen)
+		}
+		b = b[valLen:]
+
+		if depth == 0 {
+			return b0[:len(b0)-len(b)-tagLen], len(b0) - len(b), nil
+		}
+	}
+}
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/defaults.go b/demo_test/vendor/github.com/golang/protobuf/proto/defaults.go
new file mode 100644
index 0000000..d399bf0
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/defaults.go
@@ -0,0 +1,63 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	"google.golang.org/protobuf/reflect/protoreflect"
+)
+
+// SetDefaults sets unpopulated scalar fields to their default values.
+// Fields within a oneof are not set even if they have a default value.
+// SetDefaults is recursively called upon any populated message fields.
+func SetDefaults(m Message) {
+	if m != nil {
+		setDefaults(MessageReflect(m))
+	}
+}
+
+func setDefaults(m protoreflect.Message) {
+	fds := m.Descriptor().Fields()
+	for i := 0; i < fds.Len(); i++ {
+		fd := fds.Get(i)
+		if !m.Has(fd) {
+			if fd.HasDefault() && fd.ContainingOneof() == nil {
+				v := fd.Default()
+				if fd.Kind() == protoreflect.BytesKind {
+					v = protoreflect.ValueOf(append([]byte(nil), v.Bytes()...)) // copy the default bytes
+				}
+				m.Set(fd, v)
+			}
+			continue
+		}
+	}
+
+	m.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
+		switch {
+		// Handle singular message.
+		case fd.Cardinality() != protoreflect.Repeated:
+			if fd.Message() != nil {
+				setDefaults(m.Get(fd).Message())
+			}
+		// Handle list of messages.
+		case fd.IsList():
+			if fd.Message() != nil {
+				ls := m.Get(fd).List()
+				for i := 0; i < ls.Len(); i++ {
+					setDefaults(ls.Get(i).Message())
+				}
+			}
+		// Handle map of messages.
+		case fd.IsMap():
+			if fd.MapValue().Message() != nil {
+				ms := m.Get(fd).Map()
+				ms.Range(func(_ protoreflect.MapKey, v protoreflect.Value) bool {
+					setDefaults(v.Message())
+					return true
+				})
+			}
+		}
+		return true
+	})
+}
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/deprecated.go b/demo_test/vendor/github.com/golang/protobuf/proto/deprecated.go
new file mode 100644
index 0000000..a205482
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/deprecated.go
@@ -0,0 +1,92 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strconv"
+)
+
+var (
+	// Deprecated: No longer returned.
+	ErrNil = errors.New("proto: Marshal called with nil")
+
+	// Deprecated: No longer returned.
+	ErrTooLarge = errors.New("proto: message encodes to over 2 GB")
+
+	// Deprecated: No longer returned.
+	ErrInternalBadWireType = errors.New("proto: internal error: bad wiretype for oneof")
+)
+
+// Deprecated: Do not use.
+type Stats struct{ Emalloc, Dmalloc, Encode, Decode, Chit, Cmiss, Size uint64 }
+
+// Deprecated: Do not use.
+func GetStats() Stats { return Stats{} }
+
+// Deprecated: Do not use.
+func MarshalMessageSet(interface{}) ([]byte, error) {
+	return nil, errors.New("proto: not implemented")
+}
+
+// Deprecated: Do not use.
+func UnmarshalMessageSet([]byte, interface{}) error {
+	return errors.New("proto: not implemented")
+}
+
+// Deprecated: Do not use.
+func MarshalMessageSetJSON(interface{}) ([]byte, error) {
+	return nil, errors.New("proto: not implemented")
+}
+
+// Deprecated: Do not use.
+func UnmarshalMessageSetJSON([]byte, interface{}) error {
+	return errors.New("proto: not implemented")
+}
+
+// Deprecated: Do not use.
+func RegisterMessageSetType(Message, int32, string) {}
+
+// Deprecated: Do not use.
+func EnumName(m map[int32]string, v int32) string {
+	s, ok := m[v]
+	if ok {
+		return s
+	}
+	return strconv.Itoa(int(v))
+}
+
+// Deprecated: Do not use.
+func UnmarshalJSONEnum(m map[string]int32, data []byte, enumName string) (int32, error) {
+	if data[0] == '"' {
+		// New style: enums are strings.
+		var repr string
+		if err := json.Unmarshal(data, &repr); err != nil {
+			return -1, err
+		}
+		val, ok := m[repr]
+		if !ok {
+			return 0, fmt.Errorf("unrecognized enum %s value %q", enumName, repr)
+		}
+		return val, nil
+	}
+	// Old style: enums are ints.
+	var val int32
+	if err := json.Unmarshal(data, &val); err != nil {
+		return 0, fmt.Errorf("cannot unmarshal %#q into enum %s", data, enumName)
+	}
+	return val, nil
+}
+
+// Deprecated: Do not use.
+type InternalMessageInfo struct{}
+
+func (*InternalMessageInfo) DiscardUnknown(Message)                        { panic("not implemented") }
+func (*InternalMessageInfo) Marshal([]byte, Message, bool) ([]byte, error) { panic("not implemented") }
+func (*InternalMessageInfo) Merge(Message, Message)                        { panic("not implemented") }
+func (*InternalMessageInfo) Size(Message) int                              { panic("not implemented") }
+func (*InternalMessageInfo) Unmarshal(Message, []byte) error               { panic("not implemented") }
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/discard.go b/demo_test/vendor/github.com/golang/protobuf/proto/discard.go
new file mode 100644
index 0000000..2187e87
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/discard.go
@@ -0,0 +1,58 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	"google.golang.org/protobuf/reflect/protoreflect"
+)
+
+// DiscardUnknown recursively discards all unknown fields from this message
+// and all embedded messages.
+//
+// When unmarshaling a message with unrecognized fields, the tags and values
+// of such fields are preserved in the Message. This allows a later call to
+// marshal to be able to produce a message that continues to have those
+// unrecognized fields. To avoid this, DiscardUnknown is used to
+// explicitly clear the unknown fields after unmarshaling.
+func DiscardUnknown(m Message) {
+	if m != nil {
+		discardUnknown(MessageReflect(m))
+	}
+}
+
+func discardUnknown(m protoreflect.Message) {
+	m.Range(func(fd protoreflect.FieldDescriptor, val protoreflect.Value) bool {
+		switch {
+		// Handle singular message.
+		case fd.Cardinality() != protoreflect.Repeated:
+			if fd.Message() != nil {
+				discardUnknown(m.Get(fd).Message())
+			}
+		// Handle list of messages.
+		case fd.IsList():
+			if fd.Message() != nil {
+				ls := m.Get(fd).List()
+				for i := 0; i < ls.Len(); i++ {
+					discardUnknown(ls.Get(i).Message())
+				}
+			}
+		// Handle map of messages.
+		case fd.IsMap():
+			if fd.MapValue().Message() != nil {
+				ms := m.Get(fd).Map()
+				ms.Range(func(_ protoreflect.MapKey, v protoreflect.Value) bool {
+					discardUnknown(v.Message())
+					return true
+				})
+			}
+		}
+		return true
+	})
+
+	// Discard unknown fields.
+	if len(m.GetUnknown()) > 0 {
+		m.SetUnknown(nil)
+	}
+}
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/extensions.go b/demo_test/vendor/github.com/golang/protobuf/proto/extensions.go
new file mode 100644
index 0000000..5ed131c
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/extensions.go
@@ -0,0 +1,356 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+
+	"google.golang.org/protobuf/encoding/protowire"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+	"google.golang.org/protobuf/runtime/protoiface"
+	"google.golang.org/protobuf/runtime/protoimpl"
+)
+
+type (
+	// ExtensionDesc represents an extension descriptor and
+	// is used to interact with an extension field in a message.
+	//
+	// Variables of this type are generated in code by protoc-gen-go.
+	ExtensionDesc = protoimpl.ExtensionInfo
+
+	// ExtensionRange represents a range of message extensions.
+	// Used in code generated by protoc-gen-go.
+	ExtensionRange = protoiface.ExtensionRangeV1
+
+	// Deprecated: Do not use; this is an internal type.
+	Extension = protoimpl.ExtensionFieldV1
+
+	// Deprecated: Do not use; this is an internal type.
+	XXX_InternalExtensions = protoimpl.ExtensionFields
+)
+
+// ErrMissingExtension reports whether the extension was not present.
+var ErrMissingExtension = errors.New("proto: missing extension")
+
+var errNotExtendable = errors.New("proto: not an extendable proto.Message")
+
+// HasExtension reports whether the extension field is present in m
+// either as an explicitly populated field or as an unknown field.
+func HasExtension(m Message, xt *ExtensionDesc) (has bool) {
+	mr := MessageReflect(m)
+	if mr == nil || !mr.IsValid() {
+		return false
+	}
+
+	// Check whether any populated known field matches the field number.
+	xtd := xt.TypeDescriptor()
+	if isValidExtension(mr.Descriptor(), xtd) {
+		has = mr.Has(xtd)
+	} else {
+		mr.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
+			has = int32(fd.Number()) == xt.Field
+			return !has
+		})
+	}
+
+	// Check whether any unknown field matches the field number.
+	for b := mr.GetUnknown(); !has && len(b) > 0; {
+		num, _, n := protowire.ConsumeField(b)
+		has = int32(num) == xt.Field
+		b = b[n:]
+	}
+	return has
+}
+
+// ClearExtension removes the the exntesion field from m
+// either as an explicitly populated field or as an unknown field.
+func ClearExtension(m Message, xt *ExtensionDesc) {
+	mr := MessageReflect(m)
+	if mr == nil || !mr.IsValid() {
+		return
+	}
+
+	xtd := xt.TypeDescriptor()
+	if isValidExtension(mr.Descriptor(), xtd) {
+		mr.Clear(xtd)
+	} else {
+		mr.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
+			if int32(fd.Number()) == xt.Field {
+				mr.Clear(fd)
+				return false
+			}
+			return true
+		})
+	}
+	clearUnknown(mr, fieldNum(xt.Field))
+}
+
+// ClearAllExtensions clears all extensions from m.
+// This includes populated fields and unknown fields in the extension range.
+func ClearAllExtensions(m Message) {
+	mr := MessageReflect(m)
+	if mr == nil || !mr.IsValid() {
+		return
+	}
+
+	mr.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
+		if fd.IsExtension() {
+			mr.Clear(fd)
+		}
+		return true
+	})
+	clearUnknown(mr, mr.Descriptor().ExtensionRanges())
+}
+
+// GetExtension retrieves a proto2 extended field from pb.
+//
+// If the descriptor is type complete (i.e., ExtensionDesc.ExtensionType is non-nil),
+// then GetExtension parses the encoded field and returns a Go value of the specified type.
+// If the field is not present, then the default value is returned (if one is specified),
+// otherwise ErrMissingExtension is reported.
+//
+// If the descriptor is type incomplete (i.e., ExtensionDesc.ExtensionType is nil),
+// then GetExtension returns the raw encoded bytes for the extension field.
+func GetExtension(m Message, xt *ExtensionDesc) (interface{}, error) {
+	mr := MessageReflect(m)
+	if mr == nil || !mr.IsValid() || mr.Descriptor().ExtensionRanges().Len() == 0 {
+		return nil, errNotExtendable
+	}
+
+	// Retrieve the unknown fields for this extension field.
+	var bo protoreflect.RawFields
+	for bi := mr.GetUnknown(); len(bi) > 0; {
+		num, _, n := protowire.ConsumeField(bi)
+		if int32(num) == xt.Field {
+			bo = append(bo, bi[:n]...)
+		}
+		bi = bi[n:]
+	}
+
+	// For type incomplete descriptors, only retrieve the unknown fields.
+	if xt.ExtensionType == nil {
+		return []byte(bo), nil
+	}
+
+	// If the extension field only exists as unknown fields, unmarshal it.
+	// This is rarely done since proto.Unmarshal eagerly unmarshals extensions.
+	xtd := xt.TypeDescriptor()
+	if !isValidExtension(mr.Descriptor(), xtd) {
+		return nil, fmt.Errorf("proto: bad extended type; %T does not extend %T", xt.ExtendedType, m)
+	}
+	if !mr.Has(xtd) && len(bo) > 0 {
+		m2 := mr.New()
+		if err := (proto.UnmarshalOptions{
+			Resolver: extensionResolver{xt},
+		}.Unmarshal(bo, m2.Interface())); err != nil {
+			return nil, err
+		}
+		if m2.Has(xtd) {
+			mr.Set(xtd, m2.Get(xtd))
+			clearUnknown(mr, fieldNum(xt.Field))
+		}
+	}
+
+	// Check whether the message has the extension field set or a default.
+	var pv protoreflect.Value
+	switch {
+	case mr.Has(xtd):
+		pv = mr.Get(xtd)
+	case xtd.HasDefault():
+		pv = xtd.Default()
+	default:
+		return nil, ErrMissingExtension
+	}
+
+	v := xt.InterfaceOf(pv)
+	rv := reflect.ValueOf(v)
+	if isScalarKind(rv.Kind()) {
+		rv2 := reflect.New(rv.Type())
+		rv2.Elem().Set(rv)
+		v = rv2.Interface()
+	}
+	return v, nil
+}
+
+// extensionResolver is a custom extension resolver that stores a single
+// extension type that takes precedence over the global registry.
+type extensionResolver struct{ xt protoreflect.ExtensionType }
+
+func (r extensionResolver) FindExtensionByName(field protoreflect.FullName) (protoreflect.ExtensionType, error) {
+	if xtd := r.xt.TypeDescriptor(); xtd.FullName() == field {
+		return r.xt, nil
+	}
+	return protoregistry.GlobalTypes.FindExtensionByName(field)
+}
+
+func (r extensionResolver) FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error) {
+	if xtd := r.xt.TypeDescriptor(); xtd.ContainingMessage().FullName() == message && xtd.Number() == field {
+		return r.xt, nil
+	}
+	return protoregistry.GlobalTypes.FindExtensionByNumber(message, field)
+}
+
+// GetExtensions returns a list of the extensions values present in m,
+// corresponding with the provided list of extension descriptors, xts.
+// If an extension is missing in m, the corresponding value is nil.
+func GetExtensions(m Message, xts []*ExtensionDesc) ([]interface{}, error) {
+	mr := MessageReflect(m)
+	if mr == nil || !mr.IsValid() {
+		return nil, errNotExtendable
+	}
+
+	vs := make([]interface{}, len(xts))
+	for i, xt := range xts {
+		v, err := GetExtension(m, xt)
+		if err != nil {
+			if err == ErrMissingExtension {
+				continue
+			}
+			return vs, err
+		}
+		vs[i] = v
+	}
+	return vs, nil
+}
+
+// SetExtension sets an extension field in m to the provided value.
+func SetExtension(m Message, xt *ExtensionDesc, v interface{}) error {
+	mr := MessageReflect(m)
+	if mr == nil || !mr.IsValid() || mr.Descriptor().ExtensionRanges().Len() == 0 {
+		return errNotExtendable
+	}
+
+	rv := reflect.ValueOf(v)
+	if reflect.TypeOf(v) != reflect.TypeOf(xt.ExtensionType) {
+		return fmt.Errorf("proto: bad extension value type. got: %T, want: %T", v, xt.ExtensionType)
+	}
+	if rv.Kind() == reflect.Ptr {
+		if rv.IsNil() {
+			return fmt.Errorf("proto: SetExtension called with nil value of type %T", v)
+		}
+		if isScalarKind(rv.Elem().Kind()) {
+			v = rv.Elem().Interface()
+		}
+	}
+
+	xtd := xt.TypeDescriptor()
+	if !isValidExtension(mr.Descriptor(), xtd) {
+		return fmt.Errorf("proto: bad extended type; %T does not extend %T", xt.ExtendedType, m)
+	}
+	mr.Set(xtd, xt.ValueOf(v))
+	clearUnknown(mr, fieldNum(xt.Field))
+	return nil
+}
+
+// SetRawExtension inserts b into the unknown fields of m.
+//
+// Deprecated: Use Message.ProtoReflect.SetUnknown instead.
+func SetRawExtension(m Message, fnum int32, b []byte) {
+	mr := MessageReflect(m)
+	if mr == nil || !mr.IsValid() {
+		return
+	}
+
+	// Verify that the raw field is valid.
+	for b0 := b; len(b0) > 0; {
+		num, _, n := protowire.ConsumeField(b0)
+		if int32(num) != fnum {
+			panic(fmt.Sprintf("mismatching field number: got %d, want %d", num, fnum))
+		}
+		b0 = b0[n:]
+	}
+
+	ClearExtension(m, &ExtensionDesc{Field: fnum})
+	mr.SetUnknown(append(mr.GetUnknown(), b...))
+}
+
+// ExtensionDescs returns a list of extension descriptors found in m,
+// containing descriptors for both populated extension fields in m and
+// also unknown fields of m that are in the extension range.
+// For the later case, an type incomplete descriptor is provided where only
+// the ExtensionDesc.Field field is populated.
+// The order of the extension descriptors is undefined.
+func ExtensionDescs(m Message) ([]*ExtensionDesc, error) {
+	mr := MessageReflect(m)
+	if mr == nil || !mr.IsValid() || mr.Descriptor().ExtensionRanges().Len() == 0 {
+		return nil, errNotExtendable
+	}
+
+	// Collect a set of known extension descriptors.
+	extDescs := make(map[protoreflect.FieldNumber]*ExtensionDesc)
+	mr.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
+		if fd.IsExtension() {
+			xt := fd.(protoreflect.ExtensionTypeDescriptor)
+			if xd, ok := xt.Type().(*ExtensionDesc); ok {
+				extDescs[fd.Number()] = xd
+			}
+		}
+		return true
+	})
+
+	// Collect a set of unknown extension descriptors.
+	extRanges := mr.Descriptor().ExtensionRanges()
+	for b := mr.GetUnknown(); len(b) > 0; {
+		num, _, n := protowire.ConsumeField(b)
+		if extRanges.Has(num) && extDescs[num] == nil {
+			extDescs[num] = nil
+		}
+		b = b[n:]
+	}
+
+	// Transpose the set of descriptors into a list.
+	var xts []*ExtensionDesc
+	for num, xt := range extDescs {
+		if xt == nil {
+			xt = &ExtensionDesc{Field: int32(num)}
+		}
+		xts = append(xts, xt)
+	}
+	return xts, nil
+}
+
+// isValidExtension reports whether xtd is a valid extension descriptor for md.
+func isValidExtension(md protoreflect.MessageDescriptor, xtd protoreflect.ExtensionTypeDescriptor) bool {
+	return xtd.ContainingMessage() == md && md.ExtensionRanges().Has(xtd.Number())
+}
+
+// isScalarKind reports whether k is a protobuf scalar kind (except bytes).
+// This function exists for historical reasons since the representation of
+// scalars differs between v1 and v2, where v1 uses *T and v2 uses T.
+func isScalarKind(k reflect.Kind) bool {
+	switch k {
+	case reflect.Bool, reflect.Int32, reflect.Int64, reflect.Uint32, reflect.Uint64, reflect.Float32, reflect.Float64, reflect.String:
+		return true
+	default:
+		return false
+	}
+}
+
+// clearUnknown removes unknown fields from m where remover.Has reports true.
+func clearUnknown(m protoreflect.Message, remover interface {
+	Has(protoreflect.FieldNumber) bool
+}) {
+	var bo protoreflect.RawFields
+	for bi := m.GetUnknown(); len(bi) > 0; {
+		num, _, n := protowire.ConsumeField(bi)
+		if !remover.Has(num) {
+			bo = append(bo, bi[:n]...)
+		}
+		bi = bi[n:]
+	}
+	if bi := m.GetUnknown(); len(bi) != len(bo) {
+		m.SetUnknown(bo)
+	}
+}
+
+type fieldNum protoreflect.FieldNumber
+
+func (n1 fieldNum) Has(n2 protoreflect.FieldNumber) bool {
+	return protoreflect.FieldNumber(n1) == n2
+}
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/properties.go b/demo_test/vendor/github.com/golang/protobuf/proto/properties.go
new file mode 100644
index 0000000..dcdc220
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/properties.go
@@ -0,0 +1,306 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+	"sync"
+
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/runtime/protoimpl"
+)
+
+// StructProperties represents protocol buffer type information for a
+// generated protobuf message in the open-struct API.
+//
+// Deprecated: Do not use.
+type StructProperties struct {
+	// Prop are the properties for each field.
+	//
+	// Fields belonging to a oneof are stored in OneofTypes instead, with a
+	// single Properties representing the parent oneof held here.
+	//
+	// The order of Prop matches the order of fields in the Go struct.
+	// Struct fields that are not related to protobufs have a "XXX_" prefix
+	// in the Properties.Name and must be ignored by the user.
+	Prop []*Properties
+
+	// OneofTypes contains information about the oneof fields in this message.
+	// It is keyed by the protobuf field name.
+	OneofTypes map[string]*OneofProperties
+}
+
+// Properties represents the type information for a protobuf message field.
+//
+// Deprecated: Do not use.
+type Properties struct {
+	// Name is a placeholder name with little meaningful semantic value.
+	// If the name has an "XXX_" prefix, the entire Properties must be ignored.
+	Name string
+	// OrigName is the protobuf field name or oneof name.
+	OrigName string
+	// JSONName is the JSON name for the protobuf field.
+	JSONName string
+	// Enum is a placeholder name for enums.
+	// For historical reasons, this is neither the Go name for the enum,
+	// nor the protobuf name for the enum.
+	Enum string // Deprecated: Do not use.
+	// Weak contains the full name of the weakly referenced message.
+	Weak string
+	// Wire is a string representation of the wire type.
+	Wire string
+	// WireType is the protobuf wire type for the field.
+	WireType int
+	// Tag is the protobuf field number.
+	Tag int
+	// Required reports whether this is a required field.
+	Required bool
+	// Optional reports whether this is a optional field.
+	Optional bool
+	// Repeated reports whether this is a repeated field.
+	Repeated bool
+	// Packed reports whether this is a packed repeated field of scalars.
+	Packed bool
+	// Proto3 reports whether this field operates under the proto3 syntax.
+	Proto3 bool
+	// Oneof reports whether this field belongs within a oneof.
+	Oneof bool
+
+	// Default is the default value in string form.
+	Default string
+	// HasDefault reports whether the field has a default value.
+	HasDefault bool
+
+	// MapKeyProp is the properties for the key field for a map field.
+	MapKeyProp *Properties
+	// MapValProp is the properties for the value field for a map field.
+	MapValProp *Properties
+}
+
+// OneofProperties represents the type information for a protobuf oneof.
+//
+// Deprecated: Do not use.
+type OneofProperties struct {
+	// Type is a pointer to the generated wrapper type for the field value.
+	// This is nil for messages that are not in the open-struct API.
+	Type reflect.Type
+	// Field is the index into StructProperties.Prop for the containing oneof.
+	Field int
+	// Prop is the properties for the field.
+	Prop *Properties
+}
+
+// String formats the properties in the protobuf struct field tag style.
+func (p *Properties) String() string {
+	s := p.Wire
+	s += "," + strconv.Itoa(p.Tag)
+	if p.Required {
+		s += ",req"
+	}
+	if p.Optional {
+		s += ",opt"
+	}
+	if p.Repeated {
+		s += ",rep"
+	}
+	if p.Packed {
+		s += ",packed"
+	}
+	s += ",name=" + p.OrigName
+	if p.JSONName != "" {
+		s += ",json=" + p.JSONName
+	}
+	if len(p.Enum) > 0 {
+		s += ",enum=" + p.Enum
+	}
+	if len(p.Weak) > 0 {
+		s += ",weak=" + p.Weak
+	}
+	if p.Proto3 {
+		s += ",proto3"
+	}
+	if p.Oneof {
+		s += ",oneof"
+	}
+	if p.HasDefault {
+		s += ",def=" + p.Default
+	}
+	return s
+}
+
+// Parse populates p by parsing a string in the protobuf struct field tag style.
+func (p *Properties) Parse(tag string) {
+	// For example: "bytes,49,opt,name=foo,def=hello!"
+	for len(tag) > 0 {
+		i := strings.IndexByte(tag, ',')
+		if i < 0 {
+			i = len(tag)
+		}
+		switch s := tag[:i]; {
+		case strings.HasPrefix(s, "name="):
+			p.OrigName = s[len("name="):]
+		case strings.HasPrefix(s, "json="):
+			p.JSONName = s[len("json="):]
+		case strings.HasPrefix(s, "enum="):
+			p.Enum = s[len("enum="):]
+		case strings.HasPrefix(s, "weak="):
+			p.Weak = s[len("weak="):]
+		case strings.Trim(s, "0123456789") == "":
+			n, _ := strconv.ParseUint(s, 10, 32)
+			p.Tag = int(n)
+		case s == "opt":
+			p.Optional = true
+		case s == "req":
+			p.Required = true
+		case s == "rep":
+			p.Repeated = true
+		case s == "varint" || s == "zigzag32" || s == "zigzag64":
+			p.Wire = s
+			p.WireType = WireVarint
+		case s == "fixed32":
+			p.Wire = s
+			p.WireType = WireFixed32
+		case s == "fixed64":
+			p.Wire = s
+			p.WireType = WireFixed64
+		case s == "bytes":
+			p.Wire = s
+			p.WireType = WireBytes
+		case s == "group":
+			p.Wire = s
+			p.WireType = WireStartGroup
+		case s == "packed":
+			p.Packed = true
+		case s == "proto3":
+			p.Proto3 = true
+		case s == "oneof":
+			p.Oneof = true
+		case strings.HasPrefix(s, "def="):
+			// The default tag is special in that everything afterwards is the
+			// default regardless of the presence of commas.
+			p.HasDefault = true
+			p.Default, i = tag[len("def="):], len(tag)
+		}
+		tag = strings.TrimPrefix(tag[i:], ",")
+	}
+}
+
+// Init populates the properties from a protocol buffer struct tag.
+//
+// Deprecated: Do not use.
+func (p *Properties) Init(typ reflect.Type, name, tag string, f *reflect.StructField) {
+	p.Name = name
+	p.OrigName = name
+	if tag == "" {
+		return
+	}
+	p.Parse(tag)
+
+	if typ != nil && typ.Kind() == reflect.Map {
+		p.MapKeyProp = new(Properties)
+		p.MapKeyProp.Init(nil, "Key", f.Tag.Get("protobuf_key"), nil)
+		p.MapValProp = new(Properties)
+		p.MapValProp.Init(nil, "Value", f.Tag.Get("protobuf_val"), nil)
+	}
+}
+
+var propertiesCache sync.Map // map[reflect.Type]*StructProperties
+
+// GetProperties returns the list of properties for the type represented by t,
+// which must be a generated protocol buffer message in the open-struct API,
+// where protobuf message fields are represented by exported Go struct fields.
+//
+// Deprecated: Use protobuf reflection instead.
+func GetProperties(t reflect.Type) *StructProperties {
+	if p, ok := propertiesCache.Load(t); ok {
+		return p.(*StructProperties)
+	}
+	p, _ := propertiesCache.LoadOrStore(t, newProperties(t))
+	return p.(*StructProperties)
+}
+
+func newProperties(t reflect.Type) *StructProperties {
+	if t.Kind() != reflect.Struct {
+		panic(fmt.Sprintf("%v is not a generated message in the open-struct API", t))
+	}
+
+	var hasOneof bool
+	prop := new(StructProperties)
+
+	// Construct a list of properties for each field in the struct.
+	for i := 0; i < t.NumField(); i++ {
+		p := new(Properties)
+		f := t.Field(i)
+		tagField := f.Tag.Get("protobuf")
+		p.Init(f.Type, f.Name, tagField, &f)
+
+		tagOneof := f.Tag.Get("protobuf_oneof")
+		if tagOneof != "" {
+			hasOneof = true
+			p.OrigName = tagOneof
+		}
+
+		// Rename unrelated struct fields with the "XXX_" prefix since so much
+		// user code simply checks for this to exclude special fields.
+		if tagField == "" && tagOneof == "" && !strings.HasPrefix(p.Name, "XXX_") {
+			p.Name = "XXX_" + p.Name
+			p.OrigName = "XXX_" + p.OrigName
+		} else if p.Weak != "" {
+			p.Name = p.OrigName // avoid possible "XXX_" prefix on weak field
+		}
+
+		prop.Prop = append(prop.Prop, p)
+	}
+
+	// Construct a mapping of oneof field names to properties.
+	if hasOneof {
+		var oneofWrappers []interface{}
+		if fn, ok := reflect.PtrTo(t).MethodByName("XXX_OneofFuncs"); ok {
+			oneofWrappers = fn.Func.Call([]reflect.Value{reflect.Zero(fn.Type.In(0))})[3].Interface().([]interface{})
+		}
+		if fn, ok := reflect.PtrTo(t).MethodByName("XXX_OneofWrappers"); ok {
+			oneofWrappers = fn.Func.Call([]reflect.Value{reflect.Zero(fn.Type.In(0))})[0].Interface().([]interface{})
+		}
+		if m, ok := reflect.Zero(reflect.PtrTo(t)).Interface().(protoreflect.ProtoMessage); ok {
+			if m, ok := m.ProtoReflect().(interface{ ProtoMessageInfo() *protoimpl.MessageInfo }); ok {
+				oneofWrappers = m.ProtoMessageInfo().OneofWrappers
+			}
+		}
+
+		prop.OneofTypes = make(map[string]*OneofProperties)
+		for _, wrapper := range oneofWrappers {
+			p := &OneofProperties{
+				Type: reflect.ValueOf(wrapper).Type(), // *T
+				Prop: new(Properties),
+			}
+			f := p.Type.Elem().Field(0)
+			p.Prop.Name = f.Name
+			p.Prop.Parse(f.Tag.Get("protobuf"))
+
+			// Determine the struct field that contains this oneof.
+			// Each wrapper is assignable to exactly one parent field.
+			var foundOneof bool
+			for i := 0; i < t.NumField() && !foundOneof; i++ {
+				if p.Type.AssignableTo(t.Field(i).Type) {
+					p.Field = i
+					foundOneof = true
+				}
+			}
+			if !foundOneof {
+				panic(fmt.Sprintf("%v is not a generated message in the open-struct API", t))
+			}
+			prop.OneofTypes[p.Prop.OrigName] = p
+		}
+	}
+
+	return prop
+}
+
+func (sp *StructProperties) Len() int           { return len(sp.Prop) }
+func (sp *StructProperties) Less(i, j int) bool { return false }
+func (sp *StructProperties) Swap(i, j int)      { return }
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/proto.go b/demo_test/vendor/github.com/golang/protobuf/proto/proto.go
new file mode 100644
index 0000000..5aee89c
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/proto.go
@@ -0,0 +1,167 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package proto provides functionality for handling protocol buffer messages.
+// In particular, it provides marshaling and unmarshaling between a protobuf
+// message and the binary wire format.
+//
+// See https://developers.google.com/protocol-buffers/docs/gotutorial for
+// more information.
+//
+// Deprecated: Use the "google.golang.org/protobuf/proto" package instead.
+package proto
+
+import (
+	protoV2 "google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/runtime/protoiface"
+	"google.golang.org/protobuf/runtime/protoimpl"
+)
+
+const (
+	ProtoPackageIsVersion1 = true
+	ProtoPackageIsVersion2 = true
+	ProtoPackageIsVersion3 = true
+	ProtoPackageIsVersion4 = true
+)
+
+// GeneratedEnum is any enum type generated by protoc-gen-go
+// which is a named int32 kind.
+// This type exists for documentation purposes.
+type GeneratedEnum interface{}
+
+// GeneratedMessage is any message type generated by protoc-gen-go
+// which is a pointer to a named struct kind.
+// This type exists for documentation purposes.
+type GeneratedMessage interface{}
+
+// Message is a protocol buffer message.
+//
+// This is the v1 version of the message interface and is marginally better
+// than an empty interface as it lacks any method to programatically interact
+// with the contents of the message.
+//
+// A v2 message is declared in "google.golang.org/protobuf/proto".Message and
+// exposes protobuf reflection as a first-class feature of the interface.
+//
+// To convert a v1 message to a v2 message, use the MessageV2 function.
+// To convert a v2 message to a v1 message, use the MessageV1 function.
+type Message = protoiface.MessageV1
+
+// MessageV1 converts either a v1 or v2 message to a v1 message.
+// It returns nil if m is nil.
+func MessageV1(m GeneratedMessage) protoiface.MessageV1 {
+	return protoimpl.X.ProtoMessageV1Of(m)
+}
+
+// MessageV2 converts either a v1 or v2 message to a v2 message.
+// It returns nil if m is nil.
+func MessageV2(m GeneratedMessage) protoV2.Message {
+	return protoimpl.X.ProtoMessageV2Of(m)
+}
+
+// MessageReflect returns a reflective view for a message.
+// It returns nil if m is nil.
+func MessageReflect(m Message) protoreflect.Message {
+	return protoimpl.X.MessageOf(m)
+}
+
+// Marshaler is implemented by messages that can marshal themselves.
+// This interface is used by the following functions: Size, Marshal,
+// Buffer.Marshal, and Buffer.EncodeMessage.
+//
+// Deprecated: Do not implement.
+type Marshaler interface {
+	// Marshal formats the encoded bytes of the message.
+	// It should be deterministic and emit valid protobuf wire data.
+	// The caller takes ownership of the returned buffer.
+	Marshal() ([]byte, error)
+}
+
+// Unmarshaler is implemented by messages that can unmarshal themselves.
+// This interface is used by the following functions: Unmarshal, UnmarshalMerge,
+// Buffer.Unmarshal, Buffer.DecodeMessage, and Buffer.DecodeGroup.
+//
+// Deprecated: Do not implement.
+type Unmarshaler interface {
+	// Unmarshal parses the encoded bytes of the protobuf wire input.
+	// The provided buffer is only valid for during method call.
+	// It should not reset the receiver message.
+	Unmarshal([]byte) error
+}
+
+// Merger is implemented by messages that can merge themselves.
+// This interface is used by the following functions: Clone and Merge.
+//
+// Deprecated: Do not implement.
+type Merger interface {
+	// Merge merges the contents of src into the receiver message.
+	// It clones all data structures in src such that it aliases no mutable
+	// memory referenced by src.
+	Merge(src Message)
+}
+
+// RequiredNotSetError is an error type returned when
+// marshaling or unmarshaling a message with missing required fields.
+type RequiredNotSetError struct {
+	err error
+}
+
+func (e *RequiredNotSetError) Error() string {
+	if e.err != nil {
+		return e.err.Error()
+	}
+	return "proto: required field not set"
+}
+func (e *RequiredNotSetError) RequiredNotSet() bool {
+	return true
+}
+
+func checkRequiredNotSet(m protoV2.Message) error {
+	if err := protoV2.CheckInitialized(m); err != nil {
+		return &RequiredNotSetError{err: err}
+	}
+	return nil
+}
+
+// Clone returns a deep copy of src.
+func Clone(src Message) Message {
+	return MessageV1(protoV2.Clone(MessageV2(src)))
+}
+
+// Merge merges src into dst, which must be messages of the same type.
+//
+// Populated scalar fields in src are copied to dst, while populated
+// singular messages in src are merged into dst by recursively calling Merge.
+// The elements of every list field in src is appended to the corresponded
+// list fields in dst. The entries of every map field in src is copied into
+// the corresponding map field in dst, possibly replacing existing entries.
+// The unknown fields of src are appended to the unknown fields of dst.
+func Merge(dst, src Message) {
+	protoV2.Merge(MessageV2(dst), MessageV2(src))
+}
+
+// Equal reports whether two messages are equal.
+// If two messages marshal to the same bytes under deterministic serialization,
+// then Equal is guaranteed to report true.
+//
+// Two messages are equal if they are the same protobuf message type,
+// have the same set of populated known and extension field values,
+// and the same set of unknown fields values.
+//
+// Scalar values are compared with the equivalent of the == operator in Go,
+// except bytes values which are compared using bytes.Equal and
+// floating point values which specially treat NaNs as equal.
+// Message values are compared by recursively calling Equal.
+// Lists are equal if each element value is also equal.
+// Maps are equal if they have the same set of keys, where the pair of values
+// for each key is also equal.
+func Equal(x, y Message) bool {
+	return protoV2.Equal(MessageV2(x), MessageV2(y))
+}
+
+func isMessageSet(md protoreflect.MessageDescriptor) bool {
+	ms, ok := md.(interface{ IsMessageSet() bool })
+	return ok && ms.IsMessageSet()
+}
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/registry.go b/demo_test/vendor/github.com/golang/protobuf/proto/registry.go
new file mode 100644
index 0000000..abab110
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/registry.go
@@ -0,0 +1,323 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	"bytes"
+	"compress/gzip"
+	"fmt"
+	"io/ioutil"
+	"reflect"
+	"strings"
+	"sync"
+
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+	"google.golang.org/protobuf/runtime/protoimpl"
+)
+
+// filePath is the path to the proto source file.
+type filePath = string // e.g., "google/protobuf/descriptor.proto"
+
+// fileDescGZIP is the compressed contents of the encoded FileDescriptorProto.
+type fileDescGZIP = []byte
+
+var fileCache sync.Map // map[filePath]fileDescGZIP
+
+// RegisterFile is called from generated code to register the compressed
+// FileDescriptorProto with the file path for a proto source file.
+//
+// Deprecated: Use protoregistry.GlobalFiles.Register instead.
+func RegisterFile(s filePath, d fileDescGZIP) {
+	// Decompress the descriptor.
+	zr, err := gzip.NewReader(bytes.NewReader(d))
+	if err != nil {
+		panic(fmt.Sprintf("proto: invalid compressed file descriptor: %v", err))
+	}
+	b, err := ioutil.ReadAll(zr)
+	if err != nil {
+		panic(fmt.Sprintf("proto: invalid compressed file descriptor: %v", err))
+	}
+
+	// Construct a protoreflect.FileDescriptor from the raw descriptor.
+	// Note that DescBuilder.Build automatically registers the constructed
+	// file descriptor with the v2 registry.
+	protoimpl.DescBuilder{RawDescriptor: b}.Build()
+
+	// Locally cache the raw descriptor form for the file.
+	fileCache.Store(s, d)
+}
+
+// FileDescriptor returns the compressed FileDescriptorProto given the file path
+// for a proto source file. It returns nil if not found.
+//
+// Deprecated: Use protoregistry.GlobalFiles.RangeFilesByPath instead.
+func FileDescriptor(s filePath) fileDescGZIP {
+	if v, ok := fileCache.Load(s); ok {
+		return v.(fileDescGZIP)
+	}
+
+	// Find the descriptor in the v2 registry.
+	var b []byte
+	if fd, _ := protoregistry.GlobalFiles.FindFileByPath(s); fd != nil {
+		if fd, ok := fd.(interface{ ProtoLegacyRawDesc() []byte }); ok {
+			b = fd.ProtoLegacyRawDesc()
+		} else {
+			// TODO: Use protodesc.ToFileDescriptorProto to construct
+			// a descriptorpb.FileDescriptorProto and marshal it.
+			// However, doing so causes the proto package to have a dependency
+			// on descriptorpb, leading to cyclic dependency issues.
+		}
+	}
+
+	// Locally cache the raw descriptor form for the file.
+	if len(b) > 0 {
+		v, _ := fileCache.LoadOrStore(s, protoimpl.X.CompressGZIP(b))
+		return v.(fileDescGZIP)
+	}
+	return nil
+}
+
+// enumName is the name of an enum. For historical reasons, the enum name is
+// neither the full Go name nor the full protobuf name of the enum.
+// The name is the dot-separated combination of just the proto package that the
+// enum is declared within followed by the Go type name of the generated enum.
+type enumName = string // e.g., "my.proto.package.GoMessage_GoEnum"
+
+// enumsByName maps enum values by name to their numeric counterpart.
+type enumsByName = map[string]int32
+
+// enumsByNumber maps enum values by number to their name counterpart.
+type enumsByNumber = map[int32]string
+
+var enumCache sync.Map     // map[enumName]enumsByName
+var numFilesCache sync.Map // map[protoreflect.FullName]int
+
+// RegisterEnum is called from the generated code to register the mapping of
+// enum value names to enum numbers for the enum identified by s.
+//
+// Deprecated: Use protoregistry.GlobalTypes.Register instead.
+func RegisterEnum(s enumName, _ enumsByNumber, m enumsByName) {
+	if _, ok := enumCache.Load(s); ok {
+		panic("proto: duplicate enum registered: " + s)
+	}
+	enumCache.Store(s, m)
+
+	// This does not forward registration to the v2 registry since this API
+	// lacks sufficient information to construct a complete v2 enum descriptor.
+}
+
+// EnumValueMap returns the mapping from enum value names to enum numbers for
+// the enum of the given name. It returns nil if not found.
+//
+// Deprecated: Use protoregistry.GlobalTypes.FindEnumByName instead.
+func EnumValueMap(s enumName) enumsByName {
+	if v, ok := enumCache.Load(s); ok {
+		return v.(enumsByName)
+	}
+
+	// Check whether the cache is stale. If the number of files in the current
+	// package differs, then it means that some enums may have been recently
+	// registered upstream that we do not know about.
+	var protoPkg protoreflect.FullName
+	if i := strings.LastIndexByte(s, '.'); i >= 0 {
+		protoPkg = protoreflect.FullName(s[:i])
+	}
+	v, _ := numFilesCache.Load(protoPkg)
+	numFiles, _ := v.(int)
+	if protoregistry.GlobalFiles.NumFilesByPackage(protoPkg) == numFiles {
+		return nil // cache is up-to-date; was not found earlier
+	}
+
+	// Update the enum cache for all enums declared in the given proto package.
+	numFiles = 0
+	protoregistry.GlobalFiles.RangeFilesByPackage(protoPkg, func(fd protoreflect.FileDescriptor) bool {
+		walkEnums(fd, func(ed protoreflect.EnumDescriptor) {
+			name := protoimpl.X.LegacyEnumName(ed)
+			if _, ok := enumCache.Load(name); !ok {
+				m := make(enumsByName)
+				evs := ed.Values()
+				for i := evs.Len() - 1; i >= 0; i-- {
+					ev := evs.Get(i)
+					m[string(ev.Name())] = int32(ev.Number())
+				}
+				enumCache.LoadOrStore(name, m)
+			}
+		})
+		numFiles++
+		return true
+	})
+	numFilesCache.Store(protoPkg, numFiles)
+
+	// Check cache again for enum map.
+	if v, ok := enumCache.Load(s); ok {
+		return v.(enumsByName)
+	}
+	return nil
+}
+
+// walkEnums recursively walks all enums declared in d.
+func walkEnums(d interface {
+	Enums() protoreflect.EnumDescriptors
+	Messages() protoreflect.MessageDescriptors
+}, f func(protoreflect.EnumDescriptor)) {
+	eds := d.Enums()
+	for i := eds.Len() - 1; i >= 0; i-- {
+		f(eds.Get(i))
+	}
+	mds := d.Messages()
+	for i := mds.Len() - 1; i >= 0; i-- {
+		walkEnums(mds.Get(i), f)
+	}
+}
+
+// messageName is the full name of protobuf message.
+type messageName = string
+
+var messageTypeCache sync.Map // map[messageName]reflect.Type
+
+// RegisterType is called from generated code to register the message Go type
+// for a message of the given name.
+//
+// Deprecated: Use protoregistry.GlobalTypes.Register instead.
+func RegisterType(m Message, s messageName) {
+	mt := protoimpl.X.LegacyMessageTypeOf(m, protoreflect.FullName(s))
+	if err := protoregistry.GlobalTypes.RegisterMessage(mt); err != nil {
+		panic(err)
+	}
+	messageTypeCache.Store(s, reflect.TypeOf(m))
+}
+
+// RegisterMapType is called from generated code to register the Go map type
+// for a protobuf message representing a map entry.
+//
+// Deprecated: Do not use.
+func RegisterMapType(m interface{}, s messageName) {
+	t := reflect.TypeOf(m)
+	if t.Kind() != reflect.Map {
+		panic(fmt.Sprintf("invalid map kind: %v", t))
+	}
+	if _, ok := messageTypeCache.Load(s); ok {
+		panic(fmt.Errorf("proto: duplicate proto message registered: %s", s))
+	}
+	messageTypeCache.Store(s, t)
+}
+
+// MessageType returns the message type for a named message.
+// It returns nil if not found.
+//
+// Deprecated: Use protoregistry.GlobalTypes.FindMessageByName instead.
+func MessageType(s messageName) reflect.Type {
+	if v, ok := messageTypeCache.Load(s); ok {
+		return v.(reflect.Type)
+	}
+
+	// Derive the message type from the v2 registry.
+	var t reflect.Type
+	if mt, _ := protoregistry.GlobalTypes.FindMessageByName(protoreflect.FullName(s)); mt != nil {
+		t = messageGoType(mt)
+	}
+
+	// If we could not get a concrete type, it is possible that it is a
+	// pseudo-message for a map entry.
+	if t == nil {
+		d, _ := protoregistry.GlobalFiles.FindDescriptorByName(protoreflect.FullName(s))
+		if md, _ := d.(protoreflect.MessageDescriptor); md != nil && md.IsMapEntry() {
+			kt := goTypeForField(md.Fields().ByNumber(1))
+			vt := goTypeForField(md.Fields().ByNumber(2))
+			t = reflect.MapOf(kt, vt)
+		}
+	}
+
+	// Locally cache the message type for the given name.
+	if t != nil {
+		v, _ := messageTypeCache.LoadOrStore(s, t)
+		return v.(reflect.Type)
+	}
+	return nil
+}
+
+func goTypeForField(fd protoreflect.FieldDescriptor) reflect.Type {
+	switch k := fd.Kind(); k {
+	case protoreflect.EnumKind:
+		if et, _ := protoregistry.GlobalTypes.FindEnumByName(fd.Enum().FullName()); et != nil {
+			return enumGoType(et)
+		}
+		return reflect.TypeOf(protoreflect.EnumNumber(0))
+	case protoreflect.MessageKind, protoreflect.GroupKind:
+		if mt, _ := protoregistry.GlobalTypes.FindMessageByName(fd.Message().FullName()); mt != nil {
+			return messageGoType(mt)
+		}
+		return reflect.TypeOf((*protoreflect.Message)(nil)).Elem()
+	default:
+		return reflect.TypeOf(fd.Default().Interface())
+	}
+}
+
+func enumGoType(et protoreflect.EnumType) reflect.Type {
+	return reflect.TypeOf(et.New(0))
+}
+
+func messageGoType(mt protoreflect.MessageType) reflect.Type {
+	return reflect.TypeOf(MessageV1(mt.Zero().Interface()))
+}
+
+// MessageName returns the full protobuf name for the given message type.
+//
+// Deprecated: Use protoreflect.MessageDescriptor.FullName instead.
+func MessageName(m Message) messageName {
+	if m == nil {
+		return ""
+	}
+	if m, ok := m.(interface{ XXX_MessageName() messageName }); ok {
+		return m.XXX_MessageName()
+	}
+	return messageName(protoimpl.X.MessageDescriptorOf(m).FullName())
+}
+
+// RegisterExtension is called from the generated code to register
+// the extension descriptor.
+//
+// Deprecated: Use protoregistry.GlobalTypes.Register instead.
+func RegisterExtension(d *ExtensionDesc) {
+	if err := protoregistry.GlobalTypes.RegisterExtension(d); err != nil {
+		panic(err)
+	}
+}
+
+type extensionsByNumber = map[int32]*ExtensionDesc
+
+var extensionCache sync.Map // map[messageName]extensionsByNumber
+
+// RegisteredExtensions returns a map of the registered extensions for the
+// provided protobuf message, indexed by the extension field number.
+//
+// Deprecated: Use protoregistry.GlobalTypes.RangeExtensionsByMessage instead.
+func RegisteredExtensions(m Message) extensionsByNumber {
+	// Check whether the cache is stale. If the number of extensions for
+	// the given message differs, then it means that some extensions were
+	// recently registered upstream that we do not know about.
+	s := MessageName(m)
+	v, _ := extensionCache.Load(s)
+	xs, _ := v.(extensionsByNumber)
+	if protoregistry.GlobalTypes.NumExtensionsByMessage(protoreflect.FullName(s)) == len(xs) {
+		return xs // cache is up-to-date
+	}
+
+	// Cache is stale, re-compute the extensions map.
+	xs = make(extensionsByNumber)
+	protoregistry.GlobalTypes.RangeExtensionsByMessage(protoreflect.FullName(s), func(xt protoreflect.ExtensionType) bool {
+		if xd, ok := xt.(*ExtensionDesc); ok {
+			xs[int32(xt.TypeDescriptor().Number())] = xd
+		} else {
+			// TODO: This implies that the protoreflect.ExtensionType is a
+			// custom type not generated by protoc-gen-go. We could try and
+			// convert the type to an ExtensionDesc.
+		}
+		return true
+	})
+	extensionCache.Store(s, xs)
+	return xs
+}
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/text_decode.go b/demo_test/vendor/github.com/golang/protobuf/proto/text_decode.go
new file mode 100644
index 0000000..4a59310
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/text_decode.go
@@ -0,0 +1,801 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	"encoding"
+	"errors"
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+	"unicode/utf8"
+
+	"google.golang.org/protobuf/encoding/prototext"
+	protoV2 "google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+)
+
+const wrapTextUnmarshalV2 = false
+
+// ParseError is returned by UnmarshalText.
+type ParseError struct {
+	Message string
+
+	// Deprecated: Do not use.
+	Line, Offset int
+}
+
+func (e *ParseError) Error() string {
+	if wrapTextUnmarshalV2 {
+		return e.Message
+	}
+	if e.Line == 1 {
+		return fmt.Sprintf("line 1.%d: %v", e.Offset, e.Message)
+	}
+	return fmt.Sprintf("line %d: %v", e.Line, e.Message)
+}
+
+// UnmarshalText parses a proto text formatted string into m.
+func UnmarshalText(s string, m Message) error {
+	if u, ok := m.(encoding.TextUnmarshaler); ok {
+		return u.UnmarshalText([]byte(s))
+	}
+
+	m.Reset()
+	mi := MessageV2(m)
+
+	if wrapTextUnmarshalV2 {
+		err := prototext.UnmarshalOptions{
+			AllowPartial: true,
+		}.Unmarshal([]byte(s), mi)
+		if err != nil {
+			return &ParseError{Message: err.Error()}
+		}
+		return checkRequiredNotSet(mi)
+	} else {
+		if err := newTextParser(s).unmarshalMessage(mi.ProtoReflect(), ""); err != nil {
+			return err
+		}
+		return checkRequiredNotSet(mi)
+	}
+}
+
+type textParser struct {
+	s            string // remaining input
+	done         bool   // whether the parsing is finished (success or error)
+	backed       bool   // whether back() was called
+	offset, line int
+	cur          token
+}
+
+type token struct {
+	value    string
+	err      *ParseError
+	line     int    // line number
+	offset   int    // byte number from start of input, not start of line
+	unquoted string // the unquoted version of value, if it was a quoted string
+}
+
+func newTextParser(s string) *textParser {
+	p := new(textParser)
+	p.s = s
+	p.line = 1
+	p.cur.line = 1
+	return p
+}
+
+func (p *textParser) unmarshalMessage(m protoreflect.Message, terminator string) (err error) {
+	md := m.Descriptor()
+	fds := md.Fields()
+
+	// A struct is a sequence of "name: value", terminated by one of
+	// '>' or '}', or the end of the input.  A name may also be
+	// "[extension]" or "[type/url]".
+	//
+	// The whole struct can also be an expanded Any message, like:
+	// [type/url] < ... struct contents ... >
+	seen := make(map[protoreflect.FieldNumber]bool)
+	for {
+		tok := p.next()
+		if tok.err != nil {
+			return tok.err
+		}
+		if tok.value == terminator {
+			break
+		}
+		if tok.value == "[" {
+			if err := p.unmarshalExtensionOrAny(m, seen); err != nil {
+				return err
+			}
+			continue
+		}
+
+		// This is a normal, non-extension field.
+		name := protoreflect.Name(tok.value)
+		fd := fds.ByName(name)
+		switch {
+		case fd == nil:
+			gd := fds.ByName(protoreflect.Name(strings.ToLower(string(name))))
+			if gd != nil && gd.Kind() == protoreflect.GroupKind && gd.Message().Name() == name {
+				fd = gd
+			}
+		case fd.Kind() == protoreflect.GroupKind && fd.Message().Name() != name:
+			fd = nil
+		case fd.IsWeak() && fd.Message().IsPlaceholder():
+			fd = nil
+		}
+		if fd == nil {
+			typeName := string(md.FullName())
+			if m, ok := m.Interface().(Message); ok {
+				t := reflect.TypeOf(m)
+				if t.Kind() == reflect.Ptr {
+					typeName = t.Elem().String()
+				}
+			}
+			return p.errorf("unknown field name %q in %v", name, typeName)
+		}
+		if od := fd.ContainingOneof(); od != nil && m.WhichOneof(od) != nil {
+			return p.errorf("field '%s' would overwrite already parsed oneof '%s'", name, od.Name())
+		}
+		if fd.Cardinality() != protoreflect.Repeated && seen[fd.Number()] {
+			return p.errorf("non-repeated field %q was repeated", fd.Name())
+		}
+		seen[fd.Number()] = true
+
+		// Consume any colon.
+		if err := p.checkForColon(fd); err != nil {
+			return err
+		}
+
+		// Parse into the field.
+		v := m.Get(fd)
+		if !m.Has(fd) && (fd.IsList() || fd.IsMap() || fd.Message() != nil) {
+			v = m.Mutable(fd)
+		}
+		if v, err = p.unmarshalValue(v, fd); err != nil {
+			return err
+		}
+		m.Set(fd, v)
+
+		if err := p.consumeOptionalSeparator(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (p *textParser) unmarshalExtensionOrAny(m protoreflect.Message, seen map[protoreflect.FieldNumber]bool) error {
+	name, err := p.consumeExtensionOrAnyName()
+	if err != nil {
+		return err
+	}
+
+	// If it contains a slash, it's an Any type URL.
+	if slashIdx := strings.LastIndex(name, "/"); slashIdx >= 0 {
+		tok := p.next()
+		if tok.err != nil {
+			return tok.err
+		}
+		// consume an optional colon
+		if tok.value == ":" {
+			tok = p.next()
+			if tok.err != nil {
+				return tok.err
+			}
+		}
+
+		var terminator string
+		switch tok.value {
+		case "<":
+			terminator = ">"
+		case "{":
+			terminator = "}"
+		default:
+			return p.errorf("expected '{' or '<', found %q", tok.value)
+		}
+
+		mt, err := protoregistry.GlobalTypes.FindMessageByURL(name)
+		if err != nil {
+			return p.errorf("unrecognized message %q in google.protobuf.Any", name[slashIdx+len("/"):])
+		}
+		m2 := mt.New()
+		if err := p.unmarshalMessage(m2, terminator); err != nil {
+			return err
+		}
+		b, err := protoV2.Marshal(m2.Interface())
+		if err != nil {
+			return p.errorf("failed to marshal message of type %q: %v", name[slashIdx+len("/"):], err)
+		}
+
+		urlFD := m.Descriptor().Fields().ByName("type_url")
+		valFD := m.Descriptor().Fields().ByName("value")
+		if seen[urlFD.Number()] {
+			return p.errorf("Any message unpacked multiple times, or %q already set", urlFD.Name())
+		}
+		if seen[valFD.Number()] {
+			return p.errorf("Any message unpacked multiple times, or %q already set", valFD.Name())
+		}
+		m.Set(urlFD, protoreflect.ValueOfString(name))
+		m.Set(valFD, protoreflect.ValueOfBytes(b))
+		seen[urlFD.Number()] = true
+		seen[valFD.Number()] = true
+		return nil
+	}
+
+	xname := protoreflect.FullName(name)
+	xt, _ := protoregistry.GlobalTypes.FindExtensionByName(xname)
+	if xt == nil && isMessageSet(m.Descriptor()) {
+		xt, _ = protoregistry.GlobalTypes.FindExtensionByName(xname.Append("message_set_extension"))
+	}
+	if xt == nil {
+		return p.errorf("unrecognized extension %q", name)
+	}
+	fd := xt.TypeDescriptor()
+	if fd.ContainingMessage().FullName() != m.Descriptor().FullName() {
+		return p.errorf("extension field %q does not extend message %q", name, m.Descriptor().FullName())
+	}
+
+	if err := p.checkForColon(fd); err != nil {
+		return err
+	}
+
+	v := m.Get(fd)
+	if !m.Has(fd) && (fd.IsList() || fd.IsMap() || fd.Message() != nil) {
+		v = m.Mutable(fd)
+	}
+	v, err = p.unmarshalValue(v, fd)
+	if err != nil {
+		return err
+	}
+	m.Set(fd, v)
+	return p.consumeOptionalSeparator()
+}
+
+func (p *textParser) unmarshalValue(v protoreflect.Value, fd protoreflect.FieldDescriptor) (protoreflect.Value, error) {
+	tok := p.next()
+	if tok.err != nil {
+		return v, tok.err
+	}
+	if tok.value == "" {
+		return v, p.errorf("unexpected EOF")
+	}
+
+	switch {
+	case fd.IsList():
+		lv := v.List()
+		var err error
+		if tok.value == "[" {
+			// Repeated field with list notation, like [1,2,3].
+			for {
+				vv := lv.NewElement()
+				vv, err = p.unmarshalSingularValue(vv, fd)
+				if err != nil {
+					return v, err
+				}
+				lv.Append(vv)
+
+				tok := p.next()
+				if tok.err != nil {
+					return v, tok.err
+				}
+				if tok.value == "]" {
+					break
+				}
+				if tok.value != "," {
+					return v, p.errorf("Expected ']' or ',' found %q", tok.value)
+				}
+			}
+			return v, nil
+		}
+
+		// One value of the repeated field.
+		p.back()
+		vv := lv.NewElement()
+		vv, err = p.unmarshalSingularValue(vv, fd)
+		if err != nil {
+			return v, err
+		}
+		lv.Append(vv)
+		return v, nil
+	case fd.IsMap():
+		// The map entry should be this sequence of tokens:
+		//	< key : KEY value : VALUE >
+		// However, implementations may omit key or value, and technically
+		// we should support them in any order.
+		var terminator string
+		switch tok.value {
+		case "<":
+			terminator = ">"
+		case "{":
+			terminator = "}"
+		default:
+			return v, p.errorf("expected '{' or '<', found %q", tok.value)
+		}
+
+		keyFD := fd.MapKey()
+		valFD := fd.MapValue()
+
+		mv := v.Map()
+		kv := keyFD.Default()
+		vv := mv.NewValue()
+		for {
+			tok := p.next()
+			if tok.err != nil {
+				return v, tok.err
+			}
+			if tok.value == terminator {
+				break
+			}
+			var err error
+			switch tok.value {
+			case "key":
+				if err := p.consumeToken(":"); err != nil {
+					return v, err
+				}
+				if kv, err = p.unmarshalSingularValue(kv, keyFD); err != nil {
+					return v, err
+				}
+				if err := p.consumeOptionalSeparator(); err != nil {
+					return v, err
+				}
+			case "value":
+				if err := p.checkForColon(valFD); err != nil {
+					return v, err
+				}
+				if vv, err = p.unmarshalSingularValue(vv, valFD); err != nil {
+					return v, err
+				}
+				if err := p.consumeOptionalSeparator(); err != nil {
+					return v, err
+				}
+			default:
+				p.back()
+				return v, p.errorf(`expected "key", "value", or %q, found %q`, terminator, tok.value)
+			}
+		}
+		mv.Set(kv.MapKey(), vv)
+		return v, nil
+	default:
+		p.back()
+		return p.unmarshalSingularValue(v, fd)
+	}
+}
+
+func (p *textParser) unmarshalSingularValue(v protoreflect.Value, fd protoreflect.FieldDescriptor) (protoreflect.Value, error) {
+	tok := p.next()
+	if tok.err != nil {
+		return v, tok.err
+	}
+	if tok.value == "" {
+		return v, p.errorf("unexpected EOF")
+	}
+
+	switch fd.Kind() {
+	case protoreflect.BoolKind:
+		switch tok.value {
+		case "true", "1", "t", "True":
+			return protoreflect.ValueOfBool(true), nil
+		case "false", "0", "f", "False":
+			return protoreflect.ValueOfBool(false), nil
+		}
+	case protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Sfixed32Kind:
+		if x, err := strconv.ParseInt(tok.value, 0, 32); err == nil {
+			return protoreflect.ValueOfInt32(int32(x)), nil
+		}
+
+		// The C++ parser accepts large positive hex numbers that uses
+		// two's complement arithmetic to represent negative numbers.
+		// This feature is here for backwards compatibility with C++.
+		if strings.HasPrefix(tok.value, "0x") {
+			if x, err := strconv.ParseUint(tok.value, 0, 32); err == nil {
+				return protoreflect.ValueOfInt32(int32(-(int64(^x) + 1))), nil
+			}
+		}
+	case protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Sfixed64Kind:
+		if x, err := strconv.ParseInt(tok.value, 0, 64); err == nil {
+			return protoreflect.ValueOfInt64(int64(x)), nil
+		}
+
+		// The C++ parser accepts large positive hex numbers that uses
+		// two's complement arithmetic to represent negative numbers.
+		// This feature is here for backwards compatibility with C++.
+		if strings.HasPrefix(tok.value, "0x") {
+			if x, err := strconv.ParseUint(tok.value, 0, 64); err == nil {
+				return protoreflect.ValueOfInt64(int64(-(int64(^x) + 1))), nil
+			}
+		}
+	case protoreflect.Uint32Kind, protoreflect.Fixed32Kind:
+		if x, err := strconv.ParseUint(tok.value, 0, 32); err == nil {
+			return protoreflect.ValueOfUint32(uint32(x)), nil
+		}
+	case protoreflect.Uint64Kind, protoreflect.Fixed64Kind:
+		if x, err := strconv.ParseUint(tok.value, 0, 64); err == nil {
+			return protoreflect.ValueOfUint64(uint64(x)), nil
+		}
+	case protoreflect.FloatKind:
+		// Ignore 'f' for compatibility with output generated by C++,
+		// but don't remove 'f' when the value is "-inf" or "inf".
+		v := tok.value
+		if strings.HasSuffix(v, "f") && v != "-inf" && v != "inf" {
+			v = v[:len(v)-len("f")]
+		}
+		if x, err := strconv.ParseFloat(v, 32); err == nil {
+			return protoreflect.ValueOfFloat32(float32(x)), nil
+		}
+	case protoreflect.DoubleKind:
+		// Ignore 'f' for compatibility with output generated by C++,
+		// but don't remove 'f' when the value is "-inf" or "inf".
+		v := tok.value
+		if strings.HasSuffix(v, "f") && v != "-inf" && v != "inf" {
+			v = v[:len(v)-len("f")]
+		}
+		if x, err := strconv.ParseFloat(v, 64); err == nil {
+			return protoreflect.ValueOfFloat64(float64(x)), nil
+		}
+	case protoreflect.StringKind:
+		if isQuote(tok.value[0]) {
+			return protoreflect.ValueOfString(tok.unquoted), nil
+		}
+	case protoreflect.BytesKind:
+		if isQuote(tok.value[0]) {
+			return protoreflect.ValueOfBytes([]byte(tok.unquoted)), nil
+		}
+	case protoreflect.EnumKind:
+		if x, err := strconv.ParseInt(tok.value, 0, 32); err == nil {
+			return protoreflect.ValueOfEnum(protoreflect.EnumNumber(x)), nil
+		}
+		vd := fd.Enum().Values().ByName(protoreflect.Name(tok.value))
+		if vd != nil {
+			return protoreflect.ValueOfEnum(vd.Number()), nil
+		}
+	case protoreflect.MessageKind, protoreflect.GroupKind:
+		var terminator string
+		switch tok.value {
+		case "{":
+			terminator = "}"
+		case "<":
+			terminator = ">"
+		default:
+			return v, p.errorf("expected '{' or '<', found %q", tok.value)
+		}
+		err := p.unmarshalMessage(v.Message(), terminator)
+		return v, err
+	default:
+		panic(fmt.Sprintf("invalid kind %v", fd.Kind()))
+	}
+	return v, p.errorf("invalid %v: %v", fd.Kind(), tok.value)
+}
+
+// Consume a ':' from the input stream (if the next token is a colon),
+// returning an error if a colon is needed but not present.
+func (p *textParser) checkForColon(fd protoreflect.FieldDescriptor) *ParseError {
+	tok := p.next()
+	if tok.err != nil {
+		return tok.err
+	}
+	if tok.value != ":" {
+		if fd.Message() == nil {
+			return p.errorf("expected ':', found %q", tok.value)
+		}
+		p.back()
+	}
+	return nil
+}
+
+// consumeExtensionOrAnyName consumes an extension name or an Any type URL and
+// the following ']'. It returns the name or URL consumed.
+func (p *textParser) consumeExtensionOrAnyName() (string, error) {
+	tok := p.next()
+	if tok.err != nil {
+		return "", tok.err
+	}
+
+	// If extension name or type url is quoted, it's a single token.
+	if len(tok.value) > 2 && isQuote(tok.value[0]) && tok.value[len(tok.value)-1] == tok.value[0] {
+		name, err := unquoteC(tok.value[1:len(tok.value)-1], rune(tok.value[0]))
+		if err != nil {
+			return "", err
+		}
+		return name, p.consumeToken("]")
+	}
+
+	// Consume everything up to "]"
+	var parts []string
+	for tok.value != "]" {
+		parts = append(parts, tok.value)
+		tok = p.next()
+		if tok.err != nil {
+			return "", p.errorf("unrecognized type_url or extension name: %s", tok.err)
+		}
+		if p.done && tok.value != "]" {
+			return "", p.errorf("unclosed type_url or extension name")
+		}
+	}
+	return strings.Join(parts, ""), nil
+}
+
+// consumeOptionalSeparator consumes an optional semicolon or comma.
+// It is used in unmarshalMessage to provide backward compatibility.
+func (p *textParser) consumeOptionalSeparator() error {
+	tok := p.next()
+	if tok.err != nil {
+		return tok.err
+	}
+	if tok.value != ";" && tok.value != "," {
+		p.back()
+	}
+	return nil
+}
+
+func (p *textParser) errorf(format string, a ...interface{}) *ParseError {
+	pe := &ParseError{fmt.Sprintf(format, a...), p.cur.line, p.cur.offset}
+	p.cur.err = pe
+	p.done = true
+	return pe
+}
+
+func (p *textParser) skipWhitespace() {
+	i := 0
+	for i < len(p.s) && (isWhitespace(p.s[i]) || p.s[i] == '#') {
+		if p.s[i] == '#' {
+			// comment; skip to end of line or input
+			for i < len(p.s) && p.s[i] != '\n' {
+				i++
+			}
+			if i == len(p.s) {
+				break
+			}
+		}
+		if p.s[i] == '\n' {
+			p.line++
+		}
+		i++
+	}
+	p.offset += i
+	p.s = p.s[i:len(p.s)]
+	if len(p.s) == 0 {
+		p.done = true
+	}
+}
+
+func (p *textParser) advance() {
+	// Skip whitespace
+	p.skipWhitespace()
+	if p.done {
+		return
+	}
+
+	// Start of non-whitespace
+	p.cur.err = nil
+	p.cur.offset, p.cur.line = p.offset, p.line
+	p.cur.unquoted = ""
+	switch p.s[0] {
+	case '<', '>', '{', '}', ':', '[', ']', ';', ',', '/':
+		// Single symbol
+		p.cur.value, p.s = p.s[0:1], p.s[1:len(p.s)]
+	case '"', '\'':
+		// Quoted string
+		i := 1
+		for i < len(p.s) && p.s[i] != p.s[0] && p.s[i] != '\n' {
+			if p.s[i] == '\\' && i+1 < len(p.s) {
+				// skip escaped char
+				i++
+			}
+			i++
+		}
+		if i >= len(p.s) || p.s[i] != p.s[0] {
+			p.errorf("unmatched quote")
+			return
+		}
+		unq, err := unquoteC(p.s[1:i], rune(p.s[0]))
+		if err != nil {
+			p.errorf("invalid quoted string %s: %v", p.s[0:i+1], err)
+			return
+		}
+		p.cur.value, p.s = p.s[0:i+1], p.s[i+1:len(p.s)]
+		p.cur.unquoted = unq
+	default:
+		i := 0
+		for i < len(p.s) && isIdentOrNumberChar(p.s[i]) {
+			i++
+		}
+		if i == 0 {
+			p.errorf("unexpected byte %#x", p.s[0])
+			return
+		}
+		p.cur.value, p.s = p.s[0:i], p.s[i:len(p.s)]
+	}
+	p.offset += len(p.cur.value)
+}
+
+// Back off the parser by one token. Can only be done between calls to next().
+// It makes the next advance() a no-op.
+func (p *textParser) back() { p.backed = true }
+
+// Advances the parser and returns the new current token.
+func (p *textParser) next() *token {
+	if p.backed || p.done {
+		p.backed = false
+		return &p.cur
+	}
+	p.advance()
+	if p.done {
+		p.cur.value = ""
+	} else if len(p.cur.value) > 0 && isQuote(p.cur.value[0]) {
+		// Look for multiple quoted strings separated by whitespace,
+		// and concatenate them.
+		cat := p.cur
+		for {
+			p.skipWhitespace()
+			if p.done || !isQuote(p.s[0]) {
+				break
+			}
+			p.advance()
+			if p.cur.err != nil {
+				return &p.cur
+			}
+			cat.value += " " + p.cur.value
+			cat.unquoted += p.cur.unquoted
+		}
+		p.done = false // parser may have seen EOF, but we want to return cat
+		p.cur = cat
+	}
+	return &p.cur
+}
+
+func (p *textParser) consumeToken(s string) error {
+	tok := p.next()
+	if tok.err != nil {
+		return tok.err
+	}
+	if tok.value != s {
+		p.back()
+		return p.errorf("expected %q, found %q", s, tok.value)
+	}
+	return nil
+}
+
+var errBadUTF8 = errors.New("proto: bad UTF-8")
+
+func unquoteC(s string, quote rune) (string, error) {
+	// This is based on C++'s tokenizer.cc.
+	// Despite its name, this is *not* parsing C syntax.
+	// For instance, "\0" is an invalid quoted string.
+
+	// Avoid allocation in trivial cases.
+	simple := true
+	for _, r := range s {
+		if r == '\\' || r == quote {
+			simple = false
+			break
+		}
+	}
+	if simple {
+		return s, nil
+	}
+
+	buf := make([]byte, 0, 3*len(s)/2)
+	for len(s) > 0 {
+		r, n := utf8.DecodeRuneInString(s)
+		if r == utf8.RuneError && n == 1 {
+			return "", errBadUTF8
+		}
+		s = s[n:]
+		if r != '\\' {
+			if r < utf8.RuneSelf {
+				buf = append(buf, byte(r))
+			} else {
+				buf = append(buf, string(r)...)
+			}
+			continue
+		}
+
+		ch, tail, err := unescape(s)
+		if err != nil {
+			return "", err
+		}
+		buf = append(buf, ch...)
+		s = tail
+	}
+	return string(buf), nil
+}
+
+func unescape(s string) (ch string, tail string, err error) {
+	r, n := utf8.DecodeRuneInString(s)
+	if r == utf8.RuneError && n == 1 {
+		return "", "", errBadUTF8
+	}
+	s = s[n:]
+	switch r {
+	case 'a':
+		return "\a", s, nil
+	case 'b':
+		return "\b", s, nil
+	case 'f':
+		return "\f", s, nil
+	case 'n':
+		return "\n", s, nil
+	case 'r':
+		return "\r", s, nil
+	case 't':
+		return "\t", s, nil
+	case 'v':
+		return "\v", s, nil
+	case '?':
+		return "?", s, nil // trigraph workaround
+	case '\'', '"', '\\':
+		return string(r), s, nil
+	case '0', '1', '2', '3', '4', '5', '6', '7':
+		if len(s) < 2 {
+			return "", "", fmt.Errorf(`\%c requires 2 following digits`, r)
+		}
+		ss := string(r) + s[:2]
+		s = s[2:]
+		i, err := strconv.ParseUint(ss, 8, 8)
+		if err != nil {
+			return "", "", fmt.Errorf(`\%s contains non-octal digits`, ss)
+		}
+		return string([]byte{byte(i)}), s, nil
+	case 'x', 'X', 'u', 'U':
+		var n int
+		switch r {
+		case 'x', 'X':
+			n = 2
+		case 'u':
+			n = 4
+		case 'U':
+			n = 8
+		}
+		if len(s) < n {
+			return "", "", fmt.Errorf(`\%c requires %d following digits`, r, n)
+		}
+		ss := s[:n]
+		s = s[n:]
+		i, err := strconv.ParseUint(ss, 16, 64)
+		if err != nil {
+			return "", "", fmt.Errorf(`\%c%s contains non-hexadecimal digits`, r, ss)
+		}
+		if r == 'x' || r == 'X' {
+			return string([]byte{byte(i)}), s, nil
+		}
+		if i > utf8.MaxRune {
+			return "", "", fmt.Errorf(`\%c%s is not a valid Unicode code point`, r, ss)
+		}
+		return string(i), s, nil
+	}
+	return "", "", fmt.Errorf(`unknown escape \%c`, r)
+}
+
+func isIdentOrNumberChar(c byte) bool {
+	switch {
+	case 'A' <= c && c <= 'Z', 'a' <= c && c <= 'z':
+		return true
+	case '0' <= c && c <= '9':
+		return true
+	}
+	switch c {
+	case '-', '+', '.', '_':
+		return true
+	}
+	return false
+}
+
+func isWhitespace(c byte) bool {
+	switch c {
+	case ' ', '\t', '\n', '\r':
+		return true
+	}
+	return false
+}
+
+func isQuote(c byte) bool {
+	switch c {
+	case '"', '\'':
+		return true
+	}
+	return false
+}
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/text_encode.go b/demo_test/vendor/github.com/golang/protobuf/proto/text_encode.go
new file mode 100644
index 0000000..7ac02e6
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/text_encode.go
@@ -0,0 +1,560 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	"bytes"
+	"encoding"
+	"fmt"
+	"io"
+	"math"
+	"sort"
+	"strings"
+
+	"google.golang.org/protobuf/encoding/prototext"
+	"google.golang.org/protobuf/encoding/protowire"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+)
+
+const wrapTextMarshalV2 = false
+
+// TextMarshaler is a configurable text format marshaler.
+type TextMarshaler struct {
+	Compact   bool // use compact text format (one line)
+	ExpandAny bool // expand google.protobuf.Any messages of known types
+}
+
+// Marshal writes the proto text format of m to w.
+func (tm *TextMarshaler) Marshal(w io.Writer, m Message) error {
+	b, err := tm.marshal(m)
+	if len(b) > 0 {
+		if _, err := w.Write(b); err != nil {
+			return err
+		}
+	}
+	return err
+}
+
+// Text returns a proto text formatted string of m.
+func (tm *TextMarshaler) Text(m Message) string {
+	b, _ := tm.marshal(m)
+	return string(b)
+}
+
+func (tm *TextMarshaler) marshal(m Message) ([]byte, error) {
+	mr := MessageReflect(m)
+	if mr == nil || !mr.IsValid() {
+		return []byte("<nil>"), nil
+	}
+
+	if wrapTextMarshalV2 {
+		if m, ok := m.(encoding.TextMarshaler); ok {
+			return m.MarshalText()
+		}
+
+		opts := prototext.MarshalOptions{
+			AllowPartial: true,
+			EmitUnknown:  true,
+		}
+		if !tm.Compact {
+			opts.Indent = "  "
+		}
+		if !tm.ExpandAny {
+			opts.Resolver = (*protoregistry.Types)(nil)
+		}
+		return opts.Marshal(mr.Interface())
+	} else {
+		w := &textWriter{
+			compact:   tm.Compact,
+			expandAny: tm.ExpandAny,
+			complete:  true,
+		}
+
+		if m, ok := m.(encoding.TextMarshaler); ok {
+			b, err := m.MarshalText()
+			if err != nil {
+				return nil, err
+			}
+			w.Write(b)
+			return w.buf, nil
+		}
+
+		err := w.writeMessage(mr)
+		return w.buf, err
+	}
+}
+
+var (
+	defaultTextMarshaler = TextMarshaler{}
+	compactTextMarshaler = TextMarshaler{Compact: true}
+)
+
+// MarshalText writes the proto text format of m to w.
+func MarshalText(w io.Writer, pb Message) error { return defaultTextMarshaler.Marshal(w, pb) }
+
+// MarshalTextString returns a proto text formatted string of m.
+func MarshalTextString(pb Message) string { return defaultTextMarshaler.Text(pb) }
+
+// CompactText writes the compact proto text format of m to w.
+func CompactText(w io.Writer, pb Message) error { return compactTextMarshaler.Marshal(w, pb) }
+
+// CompactTextString returns a compact proto text formatted string of m.
+func CompactTextString(pb Message) string { return compactTextMarshaler.Text(pb) }
+
+var (
+	newline         = []byte("\n")
+	endBraceNewline = []byte("}\n")
+	posInf          = []byte("inf")
+	negInf          = []byte("-inf")
+	nan             = []byte("nan")
+)
+
+// textWriter is an io.Writer that tracks its indentation level.
+type textWriter struct {
+	compact   bool // same as TextMarshaler.Compact
+	expandAny bool // same as TextMarshaler.ExpandAny
+	complete  bool // whether the current position is a complete line
+	indent    int  // indentation level; never negative
+	buf       []byte
+}
+
+func (w *textWriter) Write(p []byte) (n int, _ error) {
+	newlines := bytes.Count(p, newline)
+	if newlines == 0 {
+		if !w.compact && w.complete {
+			w.writeIndent()
+		}
+		w.buf = append(w.buf, p...)
+		w.complete = false
+		return len(p), nil
+	}
+
+	frags := bytes.SplitN(p, newline, newlines+1)
+	if w.compact {
+		for i, frag := range frags {
+			if i > 0 {
+				w.buf = append(w.buf, ' ')
+				n++
+			}
+			w.buf = append(w.buf, frag...)
+			n += len(frag)
+		}
+		return n, nil
+	}
+
+	for i, frag := range frags {
+		if w.complete {
+			w.writeIndent()
+		}
+		w.buf = append(w.buf, frag...)
+		n += len(frag)
+		if i+1 < len(frags) {
+			w.buf = append(w.buf, '\n')
+			n++
+		}
+	}
+	w.complete = len(frags[len(frags)-1]) == 0
+	return n, nil
+}
+
+func (w *textWriter) WriteByte(c byte) error {
+	if w.compact && c == '\n' {
+		c = ' '
+	}
+	if !w.compact && w.complete {
+		w.writeIndent()
+	}
+	w.buf = append(w.buf, c)
+	w.complete = c == '\n'
+	return nil
+}
+
+func (w *textWriter) writeName(fd protoreflect.FieldDescriptor) {
+	if !w.compact && w.complete {
+		w.writeIndent()
+	}
+	w.complete = false
+
+	if fd.Kind() != protoreflect.GroupKind {
+		w.buf = append(w.buf, fd.Name()...)
+		w.WriteByte(':')
+	} else {
+		// Use message type name for group field name.
+		w.buf = append(w.buf, fd.Message().Name()...)
+	}
+
+	if !w.compact {
+		w.WriteByte(' ')
+	}
+}
+
+func requiresQuotes(u string) bool {
+	// When type URL contains any characters except [0-9A-Za-z./\-]*, it must be quoted.
+	for _, ch := range u {
+		switch {
+		case ch == '.' || ch == '/' || ch == '_':
+			continue
+		case '0' <= ch && ch <= '9':
+			continue
+		case 'A' <= ch && ch <= 'Z':
+			continue
+		case 'a' <= ch && ch <= 'z':
+			continue
+		default:
+			return true
+		}
+	}
+	return false
+}
+
+// writeProto3Any writes an expanded google.protobuf.Any message.
+//
+// It returns (false, nil) if sv value can't be unmarshaled (e.g. because
+// required messages are not linked in).
+//
+// It returns (true, error) when sv was written in expanded format or an error
+// was encountered.
+func (w *textWriter) writeProto3Any(m protoreflect.Message) (bool, error) {
+	md := m.Descriptor()
+	fdURL := md.Fields().ByName("type_url")
+	fdVal := md.Fields().ByName("value")
+
+	url := m.Get(fdURL).String()
+	mt, err := protoregistry.GlobalTypes.FindMessageByURL(url)
+	if err != nil {
+		return false, nil
+	}
+
+	b := m.Get(fdVal).Bytes()
+	m2 := mt.New()
+	if err := proto.Unmarshal(b, m2.Interface()); err != nil {
+		return false, nil
+	}
+	w.Write([]byte("["))
+	if requiresQuotes(url) {
+		w.writeQuotedString(url)
+	} else {
+		w.Write([]byte(url))
+	}
+	if w.compact {
+		w.Write([]byte("]:<"))
+	} else {
+		w.Write([]byte("]: <\n"))
+		w.indent++
+	}
+	if err := w.writeMessage(m2); err != nil {
+		return true, err
+	}
+	if w.compact {
+		w.Write([]byte("> "))
+	} else {
+		w.indent--
+		w.Write([]byte(">\n"))
+	}
+	return true, nil
+}
+
+func (w *textWriter) writeMessage(m protoreflect.Message) error {
+	md := m.Descriptor()
+	if w.expandAny && md.FullName() == "google.protobuf.Any" {
+		if canExpand, err := w.writeProto3Any(m); canExpand {
+			return err
+		}
+	}
+
+	fds := md.Fields()
+	for i := 0; i < fds.Len(); {
+		fd := fds.Get(i)
+		if od := fd.ContainingOneof(); od != nil {
+			fd = m.WhichOneof(od)
+			i += od.Fields().Len()
+		} else {
+			i++
+		}
+		if fd == nil || !m.Has(fd) {
+			continue
+		}
+
+		switch {
+		case fd.IsList():
+			lv := m.Get(fd).List()
+			for j := 0; j < lv.Len(); j++ {
+				w.writeName(fd)
+				v := lv.Get(j)
+				if err := w.writeSingularValue(v, fd); err != nil {
+					return err
+				}
+				w.WriteByte('\n')
+			}
+		case fd.IsMap():
+			kfd := fd.MapKey()
+			vfd := fd.MapValue()
+			mv := m.Get(fd).Map()
+
+			type entry struct{ key, val protoreflect.Value }
+			var entries []entry
+			mv.Range(func(k protoreflect.MapKey, v protoreflect.Value) bool {
+				entries = append(entries, entry{k.Value(), v})
+				return true
+			})
+			sort.Slice(entries, func(i, j int) bool {
+				switch kfd.Kind() {
+				case protoreflect.BoolKind:
+					return !entries[i].key.Bool() && entries[j].key.Bool()
+				case protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Sfixed32Kind, protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Sfixed64Kind:
+					return entries[i].key.Int() < entries[j].key.Int()
+				case protoreflect.Uint32Kind, protoreflect.Fixed32Kind, protoreflect.Uint64Kind, protoreflect.Fixed64Kind:
+					return entries[i].key.Uint() < entries[j].key.Uint()
+				case protoreflect.StringKind:
+					return entries[i].key.String() < entries[j].key.String()
+				default:
+					panic("invalid kind")
+				}
+			})
+			for _, entry := range entries {
+				w.writeName(fd)
+				w.WriteByte('<')
+				if !w.compact {
+					w.WriteByte('\n')
+				}
+				w.indent++
+				w.writeName(kfd)
+				if err := w.writeSingularValue(entry.key, kfd); err != nil {
+					return err
+				}
+				w.WriteByte('\n')
+				w.writeName(vfd)
+				if err := w.writeSingularValue(entry.val, vfd); err != nil {
+					return err
+				}
+				w.WriteByte('\n')
+				w.indent--
+				w.WriteByte('>')
+				w.WriteByte('\n')
+			}
+		default:
+			w.writeName(fd)
+			if err := w.writeSingularValue(m.Get(fd), fd); err != nil {
+				return err
+			}
+			w.WriteByte('\n')
+		}
+	}
+
+	if b := m.GetUnknown(); len(b) > 0 {
+		w.writeUnknownFields(b)
+	}
+	return w.writeExtensions(m)
+}
+
+func (w *textWriter) writeSingularValue(v protoreflect.Value, fd protoreflect.FieldDescriptor) error {
+	switch fd.Kind() {
+	case protoreflect.FloatKind, protoreflect.DoubleKind:
+		switch vf := v.Float(); {
+		case math.IsInf(vf, +1):
+			w.Write(posInf)
+		case math.IsInf(vf, -1):
+			w.Write(negInf)
+		case math.IsNaN(vf):
+			w.Write(nan)
+		default:
+			fmt.Fprint(w, v.Interface())
+		}
+	case protoreflect.StringKind:
+		// NOTE: This does not validate UTF-8 for historical reasons.
+		w.writeQuotedString(string(v.String()))
+	case protoreflect.BytesKind:
+		w.writeQuotedString(string(v.Bytes()))
+	case protoreflect.MessageKind, protoreflect.GroupKind:
+		var bra, ket byte = '<', '>'
+		if fd.Kind() == protoreflect.GroupKind {
+			bra, ket = '{', '}'
+		}
+		w.WriteByte(bra)
+		if !w.compact {
+			w.WriteByte('\n')
+		}
+		w.indent++
+		m := v.Message()
+		if m2, ok := m.Interface().(encoding.TextMarshaler); ok {
+			b, err := m2.MarshalText()
+			if err != nil {
+				return err
+			}
+			w.Write(b)
+		} else {
+			w.writeMessage(m)
+		}
+		w.indent--
+		w.WriteByte(ket)
+	case protoreflect.EnumKind:
+		if ev := fd.Enum().Values().ByNumber(v.Enum()); ev != nil {
+			fmt.Fprint(w, ev.Name())
+		} else {
+			fmt.Fprint(w, v.Enum())
+		}
+	default:
+		fmt.Fprint(w, v.Interface())
+	}
+	return nil
+}
+
+// writeQuotedString writes a quoted string in the protocol buffer text format.
+func (w *textWriter) writeQuotedString(s string) {
+	w.WriteByte('"')
+	for i := 0; i < len(s); i++ {
+		switch c := s[i]; c {
+		case '\n':
+			w.buf = append(w.buf, `\n`...)
+		case '\r':
+			w.buf = append(w.buf, `\r`...)
+		case '\t':
+			w.buf = append(w.buf, `\t`...)
+		case '"':
+			w.buf = append(w.buf, `\"`...)
+		case '\\':
+			w.buf = append(w.buf, `\\`...)
+		default:
+			if isPrint := c >= 0x20 && c < 0x7f; isPrint {
+				w.buf = append(w.buf, c)
+			} else {
+				w.buf = append(w.buf, fmt.Sprintf(`\%03o`, c)...)
+			}
+		}
+	}
+	w.WriteByte('"')
+}
+
+func (w *textWriter) writeUnknownFields(b []byte) {
+	if !w.compact {
+		fmt.Fprintf(w, "/* %d unknown bytes */\n", len(b))
+	}
+
+	for len(b) > 0 {
+		num, wtyp, n := protowire.ConsumeTag(b)
+		if n < 0 {
+			return
+		}
+		b = b[n:]
+
+		if wtyp == protowire.EndGroupType {
+			w.indent--
+			w.Write(endBraceNewline)
+			continue
+		}
+		fmt.Fprint(w, num)
+		if wtyp != protowire.StartGroupType {
+			w.WriteByte(':')
+		}
+		if !w.compact || wtyp == protowire.StartGroupType {
+			w.WriteByte(' ')
+		}
+		switch wtyp {
+		case protowire.VarintType:
+			v, n := protowire.ConsumeVarint(b)
+			if n < 0 {
+				return
+			}
+			b = b[n:]
+			fmt.Fprint(w, v)
+		case protowire.Fixed32Type:
+			v, n := protowire.ConsumeFixed32(b)
+			if n < 0 {
+				return
+			}
+			b = b[n:]
+			fmt.Fprint(w, v)
+		case protowire.Fixed64Type:
+			v, n := protowire.ConsumeFixed64(b)
+			if n < 0 {
+				return
+			}
+			b = b[n:]
+			fmt.Fprint(w, v)
+		case protowire.BytesType:
+			v, n := protowire.ConsumeBytes(b)
+			if n < 0 {
+				return
+			}
+			b = b[n:]
+			fmt.Fprintf(w, "%q", v)
+		case protowire.StartGroupType:
+			w.WriteByte('{')
+			w.indent++
+		default:
+			fmt.Fprintf(w, "/* unknown wire type %d */", wtyp)
+		}
+		w.WriteByte('\n')
+	}
+}
+
+// writeExtensions writes all the extensions in m.
+func (w *textWriter) writeExtensions(m protoreflect.Message) error {
+	md := m.Descriptor()
+	if md.ExtensionRanges().Len() == 0 {
+		return nil
+	}
+
+	type ext struct {
+		desc protoreflect.FieldDescriptor
+		val  protoreflect.Value
+	}
+	var exts []ext
+	m.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
+		if fd.IsExtension() {
+			exts = append(exts, ext{fd, v})
+		}
+		return true
+	})
+	sort.Slice(exts, func(i, j int) bool {
+		return exts[i].desc.Number() < exts[j].desc.Number()
+	})
+
+	for _, ext := range exts {
+		// For message set, use the name of the message as the extension name.
+		name := string(ext.desc.FullName())
+		if isMessageSet(ext.desc.ContainingMessage()) {
+			name = strings.TrimSuffix(name, ".message_set_extension")
+		}
+
+		if !ext.desc.IsList() {
+			if err := w.writeSingularExtension(name, ext.val, ext.desc); err != nil {
+				return err
+			}
+		} else {
+			lv := ext.val.List()
+			for i := 0; i < lv.Len(); i++ {
+				if err := w.writeSingularExtension(name, lv.Get(i), ext.desc); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func (w *textWriter) writeSingularExtension(name string, v protoreflect.Value, fd protoreflect.FieldDescriptor) error {
+	fmt.Fprintf(w, "[%s]:", name)
+	if !w.compact {
+		w.WriteByte(' ')
+	}
+	if err := w.writeSingularValue(v, fd); err != nil {
+		return err
+	}
+	w.WriteByte('\n')
+	return nil
+}
+
+func (w *textWriter) writeIndent() {
+	if !w.complete {
+		return
+	}
+	for i := 0; i < w.indent*2; i++ {
+		w.buf = append(w.buf, ' ')
+	}
+	w.complete = false
+}
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/wire.go b/demo_test/vendor/github.com/golang/protobuf/proto/wire.go
new file mode 100644
index 0000000..d7c28da
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/wire.go
@@ -0,0 +1,78 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+import (
+	protoV2 "google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/runtime/protoiface"
+)
+
+// Size returns the size in bytes of the wire-format encoding of m.
+func Size(m Message) int {
+	if m == nil {
+		return 0
+	}
+	mi := MessageV2(m)
+	return protoV2.Size(mi)
+}
+
+// Marshal returns the wire-format encoding of m.
+func Marshal(m Message) ([]byte, error) {
+	b, err := marshalAppend(nil, m, false)
+	if b == nil {
+		b = zeroBytes
+	}
+	return b, err
+}
+
+var zeroBytes = make([]byte, 0, 0)
+
+func marshalAppend(buf []byte, m Message, deterministic bool) ([]byte, error) {
+	if m == nil {
+		return nil, ErrNil
+	}
+	mi := MessageV2(m)
+	nbuf, err := protoV2.MarshalOptions{
+		Deterministic: deterministic,
+		AllowPartial:  true,
+	}.MarshalAppend(buf, mi)
+	if err != nil {
+		return buf, err
+	}
+	if len(buf) == len(nbuf) {
+		if !mi.ProtoReflect().IsValid() {
+			return buf, ErrNil
+		}
+	}
+	return nbuf, checkRequiredNotSet(mi)
+}
+
+// Unmarshal parses a wire-format message in b and places the decoded results in m.
+//
+// Unmarshal resets m before starting to unmarshal, so any existing data in m is always
+// removed. Use UnmarshalMerge to preserve and append to existing data.
+func Unmarshal(b []byte, m Message) error {
+	m.Reset()
+	return UnmarshalMerge(b, m)
+}
+
+// UnmarshalMerge parses a wire-format message in b and places the decoded results in m.
+func UnmarshalMerge(b []byte, m Message) error {
+	mi := MessageV2(m)
+	out, err := protoV2.UnmarshalOptions{
+		AllowPartial: true,
+		Merge:        true,
+	}.UnmarshalState(protoiface.UnmarshalInput{
+		Buf:     b,
+		Message: mi.ProtoReflect(),
+	})
+	if err != nil {
+		return err
+	}
+	if out.Flags&protoiface.UnmarshalInitialized > 0 {
+		return nil
+	}
+	return checkRequiredNotSet(mi)
+}
diff --git a/demo_test/vendor/github.com/golang/protobuf/proto/wrappers.go b/demo_test/vendor/github.com/golang/protobuf/proto/wrappers.go
new file mode 100644
index 0000000..398e348
--- /dev/null
+++ b/demo_test/vendor/github.com/golang/protobuf/proto/wrappers.go
@@ -0,0 +1,34 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proto
+
+// Bool stores v in a new bool value and returns a pointer to it.
+func Bool(v bool) *bool { return &v }
+
+// Int stores v in a new int32 value and returns a pointer to it.
+//
+// Deprecated: Use Int32 instead.
+func Int(v int) *int32 { return Int32(int32(v)) }
+
+// Int32 stores v in a new int32 value and returns a pointer to it.
+func Int32(v int32) *int32 { return &v }
+
+// Int64 stores v in a new int64 value and returns a pointer to it.
+func Int64(v int64) *int64 { return &v }
+
+// Uint32 stores v in a new uint32 value and returns a pointer to it.
+func Uint32(v uint32) *uint32 { return &v }
+
+// Uint64 stores v in a new uint64 value and returns a pointer to it.
+func Uint64(v uint64) *uint64 { return &v }
+
+// Float32 stores v in a new float32 value and returns a pointer to it.
+func Float32(v float32) *float32 { return &v }
+
+// Float64 stores v in a new float64 value and returns a pointer to it.
+func Float64(v float64) *float64 { return &v }
+
+// String stores v in a new string value and returns a pointer to it.
+func String(v string) *string { return &v }