diff --git a/vendor/google.golang.org/protobuf/encoding/protojson/decode.go b/vendor/google.golang.org/protobuf/encoding/protojson/decode.go
new file mode 100644
index 0000000..07da5db
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/encoding/protojson/decode.go
@@ -0,0 +1,665 @@
+// 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 protojson
+
+import (
+	"encoding/base64"
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+
+	"google.golang.org/protobuf/internal/encoding/json"
+	"google.golang.org/protobuf/internal/encoding/messageset"
+	"google.golang.org/protobuf/internal/errors"
+	"google.golang.org/protobuf/internal/flags"
+	"google.golang.org/protobuf/internal/genid"
+	"google.golang.org/protobuf/internal/pragma"
+	"google.golang.org/protobuf/internal/set"
+	"google.golang.org/protobuf/proto"
+	pref "google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+)
+
+// Unmarshal reads the given []byte into the given proto.Message.
+// The provided message must be mutable (e.g., a non-nil pointer to a message).
+func Unmarshal(b []byte, m proto.Message) error {
+	return UnmarshalOptions{}.Unmarshal(b, m)
+}
+
+// UnmarshalOptions is a configurable JSON format parser.
+type UnmarshalOptions struct {
+	pragma.NoUnkeyedLiterals
+
+	// If AllowPartial is set, input for messages that will result in missing
+	// required fields will not return an error.
+	AllowPartial bool
+
+	// If DiscardUnknown is set, unknown fields are ignored.
+	DiscardUnknown bool
+
+	// Resolver is used for looking up types when unmarshaling
+	// google.protobuf.Any messages or extension fields.
+	// If nil, this defaults to using protoregistry.GlobalTypes.
+	Resolver interface {
+		protoregistry.MessageTypeResolver
+		protoregistry.ExtensionTypeResolver
+	}
+}
+
+// Unmarshal reads the given []byte and populates the given proto.Message
+// using options in the UnmarshalOptions object.
+// It will clear the message first before setting the fields.
+// If it returns an error, the given message may be partially set.
+// The provided message must be mutable (e.g., a non-nil pointer to a message).
+func (o UnmarshalOptions) Unmarshal(b []byte, m proto.Message) error {
+	return o.unmarshal(b, m)
+}
+
+// unmarshal is a centralized function that all unmarshal operations go through.
+// For profiling purposes, avoid changing the name of this function or
+// introducing other code paths for unmarshal that do not go through this.
+func (o UnmarshalOptions) unmarshal(b []byte, m proto.Message) error {
+	proto.Reset(m)
+
+	if o.Resolver == nil {
+		o.Resolver = protoregistry.GlobalTypes
+	}
+
+	dec := decoder{json.NewDecoder(b), o}
+	if err := dec.unmarshalMessage(m.ProtoReflect(), false); err != nil {
+		return err
+	}
+
+	// Check for EOF.
+	tok, err := dec.Read()
+	if err != nil {
+		return err
+	}
+	if tok.Kind() != json.EOF {
+		return dec.unexpectedTokenError(tok)
+	}
+
+	if o.AllowPartial {
+		return nil
+	}
+	return proto.CheckInitialized(m)
+}
+
+type decoder struct {
+	*json.Decoder
+	opts UnmarshalOptions
+}
+
+// newError returns an error object with position info.
+func (d decoder) newError(pos int, f string, x ...interface{}) error {
+	line, column := d.Position(pos)
+	head := fmt.Sprintf("(line %d:%d): ", line, column)
+	return errors.New(head+f, x...)
+}
+
+// unexpectedTokenError returns a syntax error for the given unexpected token.
+func (d decoder) unexpectedTokenError(tok json.Token) error {
+	return d.syntaxError(tok.Pos(), "unexpected token %s", tok.RawString())
+}
+
+// syntaxError returns a syntax error for given position.
+func (d decoder) syntaxError(pos int, f string, x ...interface{}) error {
+	line, column := d.Position(pos)
+	head := fmt.Sprintf("syntax error (line %d:%d): ", line, column)
+	return errors.New(head+f, x...)
+}
+
+// unmarshalMessage unmarshals a message into the given protoreflect.Message.
+func (d decoder) unmarshalMessage(m pref.Message, skipTypeURL bool) error {
+	if unmarshal := wellKnownTypeUnmarshaler(m.Descriptor().FullName()); unmarshal != nil {
+		return unmarshal(d, m)
+	}
+
+	tok, err := d.Read()
+	if err != nil {
+		return err
+	}
+	if tok.Kind() != json.ObjectOpen {
+		return d.unexpectedTokenError(tok)
+	}
+
+	messageDesc := m.Descriptor()
+	if !flags.ProtoLegacy && messageset.IsMessageSet(messageDesc) {
+		return errors.New("no support for proto1 MessageSets")
+	}
+
+	var seenNums set.Ints
+	var seenOneofs set.Ints
+	fieldDescs := messageDesc.Fields()
+	for {
+		// Read field name.
+		tok, err := d.Read()
+		if err != nil {
+			return err
+		}
+		switch tok.Kind() {
+		default:
+			return d.unexpectedTokenError(tok)
+		case json.ObjectClose:
+			return nil
+		case json.Name:
+			// Continue below.
+		}
+
+		name := tok.Name()
+		// Unmarshaling a non-custom embedded message in Any will contain the
+		// JSON field "@type" which should be skipped because it is not a field
+		// of the embedded message, but simply an artifact of the Any format.
+		if skipTypeURL && name == "@type" {
+			d.Read()
+			continue
+		}
+
+		// Get the FieldDescriptor.
+		var fd pref.FieldDescriptor
+		if strings.HasPrefix(name, "[") && strings.HasSuffix(name, "]") {
+			// Only extension names are in [name] format.
+			extName := pref.FullName(name[1 : len(name)-1])
+			extType, err := d.opts.Resolver.FindExtensionByName(extName)
+			if err != nil && err != protoregistry.NotFound {
+				return d.newError(tok.Pos(), "unable to resolve %s: %v", tok.RawString(), err)
+			}
+			if extType != nil {
+				fd = extType.TypeDescriptor()
+				if !messageDesc.ExtensionRanges().Has(fd.Number()) || fd.ContainingMessage().FullName() != messageDesc.FullName() {
+					return d.newError(tok.Pos(), "message %v cannot be extended by %v", messageDesc.FullName(), fd.FullName())
+				}
+			}
+		} else {
+			// The name can either be the JSON name or the proto field name.
+			fd = fieldDescs.ByJSONName(name)
+			if fd == nil {
+				fd = fieldDescs.ByTextName(name)
+			}
+		}
+		if flags.ProtoLegacy {
+			if fd != nil && fd.IsWeak() && fd.Message().IsPlaceholder() {
+				fd = nil // reset since the weak reference is not linked in
+			}
+		}
+
+		if fd == nil {
+			// Field is unknown.
+			if d.opts.DiscardUnknown {
+				if err := d.skipJSONValue(); err != nil {
+					return err
+				}
+				continue
+			}
+			return d.newError(tok.Pos(), "unknown field %v", tok.RawString())
+		}
+
+		// Do not allow duplicate fields.
+		num := uint64(fd.Number())
+		if seenNums.Has(num) {
+			return d.newError(tok.Pos(), "duplicate field %v", tok.RawString())
+		}
+		seenNums.Set(num)
+
+		// No need to set values for JSON null unless the field type is
+		// google.protobuf.Value or google.protobuf.NullValue.
+		if tok, _ := d.Peek(); tok.Kind() == json.Null && !isKnownValue(fd) && !isNullValue(fd) {
+			d.Read()
+			continue
+		}
+
+		switch {
+		case fd.IsList():
+			list := m.Mutable(fd).List()
+			if err := d.unmarshalList(list, fd); err != nil {
+				return err
+			}
+		case fd.IsMap():
+			mmap := m.Mutable(fd).Map()
+			if err := d.unmarshalMap(mmap, fd); err != nil {
+				return err
+			}
+		default:
+			// If field is a oneof, check if it has already been set.
+			if od := fd.ContainingOneof(); od != nil {
+				idx := uint64(od.Index())
+				if seenOneofs.Has(idx) {
+					return d.newError(tok.Pos(), "error parsing %s, oneof %v is already set", tok.RawString(), od.FullName())
+				}
+				seenOneofs.Set(idx)
+			}
+
+			// Required or optional fields.
+			if err := d.unmarshalSingular(m, fd); err != nil {
+				return err
+			}
+		}
+	}
+}
+
+func isKnownValue(fd pref.FieldDescriptor) bool {
+	md := fd.Message()
+	return md != nil && md.FullName() == genid.Value_message_fullname
+}
+
+func isNullValue(fd pref.FieldDescriptor) bool {
+	ed := fd.Enum()
+	return ed != nil && ed.FullName() == genid.NullValue_enum_fullname
+}
+
+// unmarshalSingular unmarshals to the non-repeated field specified
+// by the given FieldDescriptor.
+func (d decoder) unmarshalSingular(m pref.Message, fd pref.FieldDescriptor) error {
+	var val pref.Value
+	var err error
+	switch fd.Kind() {
+	case pref.MessageKind, pref.GroupKind:
+		val = m.NewField(fd)
+		err = d.unmarshalMessage(val.Message(), false)
+	default:
+		val, err = d.unmarshalScalar(fd)
+	}
+
+	if err != nil {
+		return err
+	}
+	m.Set(fd, val)
+	return nil
+}
+
+// unmarshalScalar unmarshals to a scalar/enum protoreflect.Value specified by
+// the given FieldDescriptor.
+func (d decoder) unmarshalScalar(fd pref.FieldDescriptor) (pref.Value, error) {
+	const b32 int = 32
+	const b64 int = 64
+
+	tok, err := d.Read()
+	if err != nil {
+		return pref.Value{}, err
+	}
+
+	kind := fd.Kind()
+	switch kind {
+	case pref.BoolKind:
+		if tok.Kind() == json.Bool {
+			return pref.ValueOfBool(tok.Bool()), nil
+		}
+
+	case pref.Int32Kind, pref.Sint32Kind, pref.Sfixed32Kind:
+		if v, ok := unmarshalInt(tok, b32); ok {
+			return v, nil
+		}
+
+	case pref.Int64Kind, pref.Sint64Kind, pref.Sfixed64Kind:
+		if v, ok := unmarshalInt(tok, b64); ok {
+			return v, nil
+		}
+
+	case pref.Uint32Kind, pref.Fixed32Kind:
+		if v, ok := unmarshalUint(tok, b32); ok {
+			return v, nil
+		}
+
+	case pref.Uint64Kind, pref.Fixed64Kind:
+		if v, ok := unmarshalUint(tok, b64); ok {
+			return v, nil
+		}
+
+	case pref.FloatKind:
+		if v, ok := unmarshalFloat(tok, b32); ok {
+			return v, nil
+		}
+
+	case pref.DoubleKind:
+		if v, ok := unmarshalFloat(tok, b64); ok {
+			return v, nil
+		}
+
+	case pref.StringKind:
+		if tok.Kind() == json.String {
+			return pref.ValueOfString(tok.ParsedString()), nil
+		}
+
+	case pref.BytesKind:
+		if v, ok := unmarshalBytes(tok); ok {
+			return v, nil
+		}
+
+	case pref.EnumKind:
+		if v, ok := unmarshalEnum(tok, fd); ok {
+			return v, nil
+		}
+
+	default:
+		panic(fmt.Sprintf("unmarshalScalar: invalid scalar kind %v", kind))
+	}
+
+	return pref.Value{}, d.newError(tok.Pos(), "invalid value for %v type: %v", kind, tok.RawString())
+}
+
+func unmarshalInt(tok json.Token, bitSize int) (pref.Value, bool) {
+	switch tok.Kind() {
+	case json.Number:
+		return getInt(tok, bitSize)
+
+	case json.String:
+		// Decode number from string.
+		s := strings.TrimSpace(tok.ParsedString())
+		if len(s) != len(tok.ParsedString()) {
+			return pref.Value{}, false
+		}
+		dec := json.NewDecoder([]byte(s))
+		tok, err := dec.Read()
+		if err != nil {
+			return pref.Value{}, false
+		}
+		return getInt(tok, bitSize)
+	}
+	return pref.Value{}, false
+}
+
+func getInt(tok json.Token, bitSize int) (pref.Value, bool) {
+	n, ok := tok.Int(bitSize)
+	if !ok {
+		return pref.Value{}, false
+	}
+	if bitSize == 32 {
+		return pref.ValueOfInt32(int32(n)), true
+	}
+	return pref.ValueOfInt64(n), true
+}
+
+func unmarshalUint(tok json.Token, bitSize int) (pref.Value, bool) {
+	switch tok.Kind() {
+	case json.Number:
+		return getUint(tok, bitSize)
+
+	case json.String:
+		// Decode number from string.
+		s := strings.TrimSpace(tok.ParsedString())
+		if len(s) != len(tok.ParsedString()) {
+			return pref.Value{}, false
+		}
+		dec := json.NewDecoder([]byte(s))
+		tok, err := dec.Read()
+		if err != nil {
+			return pref.Value{}, false
+		}
+		return getUint(tok, bitSize)
+	}
+	return pref.Value{}, false
+}
+
+func getUint(tok json.Token, bitSize int) (pref.Value, bool) {
+	n, ok := tok.Uint(bitSize)
+	if !ok {
+		return pref.Value{}, false
+	}
+	if bitSize == 32 {
+		return pref.ValueOfUint32(uint32(n)), true
+	}
+	return pref.ValueOfUint64(n), true
+}
+
+func unmarshalFloat(tok json.Token, bitSize int) (pref.Value, bool) {
+	switch tok.Kind() {
+	case json.Number:
+		return getFloat(tok, bitSize)
+
+	case json.String:
+		s := tok.ParsedString()
+		switch s {
+		case "NaN":
+			if bitSize == 32 {
+				return pref.ValueOfFloat32(float32(math.NaN())), true
+			}
+			return pref.ValueOfFloat64(math.NaN()), true
+		case "Infinity":
+			if bitSize == 32 {
+				return pref.ValueOfFloat32(float32(math.Inf(+1))), true
+			}
+			return pref.ValueOfFloat64(math.Inf(+1)), true
+		case "-Infinity":
+			if bitSize == 32 {
+				return pref.ValueOfFloat32(float32(math.Inf(-1))), true
+			}
+			return pref.ValueOfFloat64(math.Inf(-1)), true
+		}
+
+		// Decode number from string.
+		if len(s) != len(strings.TrimSpace(s)) {
+			return pref.Value{}, false
+		}
+		dec := json.NewDecoder([]byte(s))
+		tok, err := dec.Read()
+		if err != nil {
+			return pref.Value{}, false
+		}
+		return getFloat(tok, bitSize)
+	}
+	return pref.Value{}, false
+}
+
+func getFloat(tok json.Token, bitSize int) (pref.Value, bool) {
+	n, ok := tok.Float(bitSize)
+	if !ok {
+		return pref.Value{}, false
+	}
+	if bitSize == 32 {
+		return pref.ValueOfFloat32(float32(n)), true
+	}
+	return pref.ValueOfFloat64(n), true
+}
+
+func unmarshalBytes(tok json.Token) (pref.Value, bool) {
+	if tok.Kind() != json.String {
+		return pref.Value{}, false
+	}
+
+	s := tok.ParsedString()
+	enc := base64.StdEncoding
+	if strings.ContainsAny(s, "-_") {
+		enc = base64.URLEncoding
+	}
+	if len(s)%4 != 0 {
+		enc = enc.WithPadding(base64.NoPadding)
+	}
+	b, err := enc.DecodeString(s)
+	if err != nil {
+		return pref.Value{}, false
+	}
+	return pref.ValueOfBytes(b), true
+}
+
+func unmarshalEnum(tok json.Token, fd pref.FieldDescriptor) (pref.Value, bool) {
+	switch tok.Kind() {
+	case json.String:
+		// Lookup EnumNumber based on name.
+		s := tok.ParsedString()
+		if enumVal := fd.Enum().Values().ByName(pref.Name(s)); enumVal != nil {
+			return pref.ValueOfEnum(enumVal.Number()), true
+		}
+
+	case json.Number:
+		if n, ok := tok.Int(32); ok {
+			return pref.ValueOfEnum(pref.EnumNumber(n)), true
+		}
+
+	case json.Null:
+		// This is only valid for google.protobuf.NullValue.
+		if isNullValue(fd) {
+			return pref.ValueOfEnum(0), true
+		}
+	}
+
+	return pref.Value{}, false
+}
+
+func (d decoder) unmarshalList(list pref.List, fd pref.FieldDescriptor) error {
+	tok, err := d.Read()
+	if err != nil {
+		return err
+	}
+	if tok.Kind() != json.ArrayOpen {
+		return d.unexpectedTokenError(tok)
+	}
+
+	switch fd.Kind() {
+	case pref.MessageKind, pref.GroupKind:
+		for {
+			tok, err := d.Peek()
+			if err != nil {
+				return err
+			}
+
+			if tok.Kind() == json.ArrayClose {
+				d.Read()
+				return nil
+			}
+
+			val := list.NewElement()
+			if err := d.unmarshalMessage(val.Message(), false); err != nil {
+				return err
+			}
+			list.Append(val)
+		}
+	default:
+		for {
+			tok, err := d.Peek()
+			if err != nil {
+				return err
+			}
+
+			if tok.Kind() == json.ArrayClose {
+				d.Read()
+				return nil
+			}
+
+			val, err := d.unmarshalScalar(fd)
+			if err != nil {
+				return err
+			}
+			list.Append(val)
+		}
+	}
+
+	return nil
+}
+
+func (d decoder) unmarshalMap(mmap pref.Map, fd pref.FieldDescriptor) error {
+	tok, err := d.Read()
+	if err != nil {
+		return err
+	}
+	if tok.Kind() != json.ObjectOpen {
+		return d.unexpectedTokenError(tok)
+	}
+
+	// Determine ahead whether map entry is a scalar type or a message type in
+	// order to call the appropriate unmarshalMapValue func inside the for loop
+	// below.
+	var unmarshalMapValue func() (pref.Value, error)
+	switch fd.MapValue().Kind() {
+	case pref.MessageKind, pref.GroupKind:
+		unmarshalMapValue = func() (pref.Value, error) {
+			val := mmap.NewValue()
+			if err := d.unmarshalMessage(val.Message(), false); err != nil {
+				return pref.Value{}, err
+			}
+			return val, nil
+		}
+	default:
+		unmarshalMapValue = func() (pref.Value, error) {
+			return d.unmarshalScalar(fd.MapValue())
+		}
+	}
+
+Loop:
+	for {
+		// Read field name.
+		tok, err := d.Read()
+		if err != nil {
+			return err
+		}
+		switch tok.Kind() {
+		default:
+			return d.unexpectedTokenError(tok)
+		case json.ObjectClose:
+			break Loop
+		case json.Name:
+			// Continue.
+		}
+
+		// Unmarshal field name.
+		pkey, err := d.unmarshalMapKey(tok, fd.MapKey())
+		if err != nil {
+			return err
+		}
+
+		// Check for duplicate field name.
+		if mmap.Has(pkey) {
+			return d.newError(tok.Pos(), "duplicate map key %v", tok.RawString())
+		}
+
+		// Read and unmarshal field value.
+		pval, err := unmarshalMapValue()
+		if err != nil {
+			return err
+		}
+
+		mmap.Set(pkey, pval)
+	}
+
+	return nil
+}
+
+// unmarshalMapKey converts given token of Name kind into a protoreflect.MapKey.
+// A map key type is any integral or string type.
+func (d decoder) unmarshalMapKey(tok json.Token, fd pref.FieldDescriptor) (pref.MapKey, error) {
+	const b32 = 32
+	const b64 = 64
+	const base10 = 10
+
+	name := tok.Name()
+	kind := fd.Kind()
+	switch kind {
+	case pref.StringKind:
+		return pref.ValueOfString(name).MapKey(), nil
+
+	case pref.BoolKind:
+		switch name {
+		case "true":
+			return pref.ValueOfBool(true).MapKey(), nil
+		case "false":
+			return pref.ValueOfBool(false).MapKey(), nil
+		}
+
+	case pref.Int32Kind, pref.Sint32Kind, pref.Sfixed32Kind:
+		if n, err := strconv.ParseInt(name, base10, b32); err == nil {
+			return pref.ValueOfInt32(int32(n)).MapKey(), nil
+		}
+
+	case pref.Int64Kind, pref.Sint64Kind, pref.Sfixed64Kind:
+		if n, err := strconv.ParseInt(name, base10, b64); err == nil {
+			return pref.ValueOfInt64(int64(n)).MapKey(), nil
+		}
+
+	case pref.Uint32Kind, pref.Fixed32Kind:
+		if n, err := strconv.ParseUint(name, base10, b32); err == nil {
+			return pref.ValueOfUint32(uint32(n)).MapKey(), nil
+		}
+
+	case pref.Uint64Kind, pref.Fixed64Kind:
+		if n, err := strconv.ParseUint(name, base10, b64); err == nil {
+			return pref.ValueOfUint64(uint64(n)).MapKey(), nil
+		}
+
+	default:
+		panic(fmt.Sprintf("invalid kind for map key: %v", kind))
+	}
+
+	return pref.MapKey{}, d.newError(tok.Pos(), "invalid value for %v key: %s", kind, tok.RawString())
+}
diff --git a/vendor/google.golang.org/protobuf/encoding/protojson/doc.go b/vendor/google.golang.org/protobuf/encoding/protojson/doc.go
new file mode 100644
index 0000000..00ea2fe
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/encoding/protojson/doc.go
@@ -0,0 +1,11 @@
+// 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 protojson marshals and unmarshals protocol buffer messages as JSON
+// format. It follows the guide at
+// https://developers.google.com/protocol-buffers/docs/proto3#json.
+//
+// This package produces a different output than the standard "encoding/json"
+// package, which does not operate correctly on protocol buffer messages.
+package protojson
diff --git a/vendor/google.golang.org/protobuf/encoding/protojson/encode.go b/vendor/google.golang.org/protobuf/encoding/protojson/encode.go
new file mode 100644
index 0000000..ba971f0
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/encoding/protojson/encode.go
@@ -0,0 +1,344 @@
+// 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 protojson
+
+import (
+	"encoding/base64"
+	"fmt"
+
+	"google.golang.org/protobuf/internal/encoding/json"
+	"google.golang.org/protobuf/internal/encoding/messageset"
+	"google.golang.org/protobuf/internal/errors"
+	"google.golang.org/protobuf/internal/filedesc"
+	"google.golang.org/protobuf/internal/flags"
+	"google.golang.org/protobuf/internal/genid"
+	"google.golang.org/protobuf/internal/order"
+	"google.golang.org/protobuf/internal/pragma"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	pref "google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+)
+
+const defaultIndent = "  "
+
+// Format formats the message as a multiline string.
+// This function is only intended for human consumption and ignores errors.
+// Do not depend on the output being stable. It may change over time across
+// different versions of the program.
+func Format(m proto.Message) string {
+	return MarshalOptions{Multiline: true}.Format(m)
+}
+
+// Marshal writes the given proto.Message in JSON format using default options.
+// Do not depend on the output being stable. It may change over time across
+// different versions of the program.
+func Marshal(m proto.Message) ([]byte, error) {
+	return MarshalOptions{}.Marshal(m)
+}
+
+// MarshalOptions is a configurable JSON format marshaler.
+type MarshalOptions struct {
+	pragma.NoUnkeyedLiterals
+
+	// Multiline specifies whether the marshaler should format the output in
+	// indented-form with every textual element on a new line.
+	// If Indent is an empty string, then an arbitrary indent is chosen.
+	Multiline bool
+
+	// Indent specifies the set of indentation characters to use in a multiline
+	// formatted output such that every entry is preceded by Indent and
+	// terminated by a newline. If non-empty, then Multiline is treated as true.
+	// Indent can only be composed of space or tab characters.
+	Indent string
+
+	// AllowPartial allows messages that have missing required fields to marshal
+	// without returning an error. If AllowPartial is false (the default),
+	// Marshal will return error if there are any missing required fields.
+	AllowPartial bool
+
+	// UseProtoNames uses proto field name instead of lowerCamelCase name in JSON
+	// field names.
+	UseProtoNames bool
+
+	// UseEnumNumbers emits enum values as numbers.
+	UseEnumNumbers bool
+
+	// EmitUnpopulated specifies whether to emit unpopulated fields. It does not
+	// emit unpopulated oneof fields or unpopulated extension fields.
+	// The JSON value emitted for unpopulated fields are as follows:
+	//  ╔═══════╤════════════════════════════╗
+	//  ║ JSON  │ Protobuf field             ║
+	//  ╠═══════╪════════════════════════════╣
+	//  ║ false │ proto3 boolean fields      ║
+	//  ║ 0     │ proto3 numeric fields      ║
+	//  ║ ""    │ proto3 string/bytes fields ║
+	//  ║ null  │ proto2 scalar fields       ║
+	//  ║ null  │ message fields             ║
+	//  ║ []    │ list fields                ║
+	//  ║ {}    │ map fields                 ║
+	//  ╚═══════╧════════════════════════════╝
+	EmitUnpopulated bool
+
+	// Resolver is used for looking up types when expanding google.protobuf.Any
+	// messages. If nil, this defaults to using protoregistry.GlobalTypes.
+	Resolver interface {
+		protoregistry.ExtensionTypeResolver
+		protoregistry.MessageTypeResolver
+	}
+}
+
+// Format formats the message as a string.
+// This method is only intended for human consumption and ignores errors.
+// Do not depend on the output being stable. It may change over time across
+// different versions of the program.
+func (o MarshalOptions) Format(m proto.Message) string {
+	if m == nil || !m.ProtoReflect().IsValid() {
+		return "<nil>" // invalid syntax, but okay since this is for debugging
+	}
+	o.AllowPartial = true
+	b, _ := o.Marshal(m)
+	return string(b)
+}
+
+// Marshal marshals the given proto.Message in the JSON format using options in
+// MarshalOptions. Do not depend on the output being stable. It may change over
+// time across different versions of the program.
+func (o MarshalOptions) Marshal(m proto.Message) ([]byte, error) {
+	return o.marshal(m)
+}
+
+// marshal is a centralized function that all marshal operations go through.
+// For profiling purposes, avoid changing the name of this function or
+// introducing other code paths for marshal that do not go through this.
+func (o MarshalOptions) marshal(m proto.Message) ([]byte, error) {
+	if o.Multiline && o.Indent == "" {
+		o.Indent = defaultIndent
+	}
+	if o.Resolver == nil {
+		o.Resolver = protoregistry.GlobalTypes
+	}
+
+	internalEnc, err := json.NewEncoder(o.Indent)
+	if err != nil {
+		return nil, err
+	}
+
+	// Treat nil message interface as an empty message,
+	// in which case the output in an empty JSON object.
+	if m == nil {
+		return []byte("{}"), nil
+	}
+
+	enc := encoder{internalEnc, o}
+	if err := enc.marshalMessage(m.ProtoReflect(), ""); err != nil {
+		return nil, err
+	}
+	if o.AllowPartial {
+		return enc.Bytes(), nil
+	}
+	return enc.Bytes(), proto.CheckInitialized(m)
+}
+
+type encoder struct {
+	*json.Encoder
+	opts MarshalOptions
+}
+
+// typeFieldDesc is a synthetic field descriptor used for the "@type" field.
+var typeFieldDesc = func() protoreflect.FieldDescriptor {
+	var fd filedesc.Field
+	fd.L0.FullName = "@type"
+	fd.L0.Index = -1
+	fd.L1.Cardinality = protoreflect.Optional
+	fd.L1.Kind = protoreflect.StringKind
+	return &fd
+}()
+
+// typeURLFieldRanger wraps a protoreflect.Message and modifies its Range method
+// to additionally iterate over a synthetic field for the type URL.
+type typeURLFieldRanger struct {
+	order.FieldRanger
+	typeURL string
+}
+
+func (m typeURLFieldRanger) Range(f func(pref.FieldDescriptor, pref.Value) bool) {
+	if !f(typeFieldDesc, pref.ValueOfString(m.typeURL)) {
+		return
+	}
+	m.FieldRanger.Range(f)
+}
+
+// unpopulatedFieldRanger wraps a protoreflect.Message and modifies its Range
+// method to additionally iterate over unpopulated fields.
+type unpopulatedFieldRanger struct{ pref.Message }
+
+func (m unpopulatedFieldRanger) Range(f func(pref.FieldDescriptor, pref.Value) bool) {
+	fds := m.Descriptor().Fields()
+	for i := 0; i < fds.Len(); i++ {
+		fd := fds.Get(i)
+		if m.Has(fd) || fd.ContainingOneof() != nil {
+			continue // ignore populated fields and fields within a oneofs
+		}
+
+		v := m.Get(fd)
+		isProto2Scalar := fd.Syntax() == pref.Proto2 && fd.Default().IsValid()
+		isSingularMessage := fd.Cardinality() != pref.Repeated && fd.Message() != nil
+		if isProto2Scalar || isSingularMessage {
+			v = pref.Value{} // use invalid value to emit null
+		}
+		if !f(fd, v) {
+			return
+		}
+	}
+	m.Message.Range(f)
+}
+
+// marshalMessage marshals the fields in the given protoreflect.Message.
+// If the typeURL is non-empty, then a synthetic "@type" field is injected
+// containing the URL as the value.
+func (e encoder) marshalMessage(m pref.Message, typeURL string) error {
+	if !flags.ProtoLegacy && messageset.IsMessageSet(m.Descriptor()) {
+		return errors.New("no support for proto1 MessageSets")
+	}
+
+	if marshal := wellKnownTypeMarshaler(m.Descriptor().FullName()); marshal != nil {
+		return marshal(e, m)
+	}
+
+	e.StartObject()
+	defer e.EndObject()
+
+	var fields order.FieldRanger = m
+	if e.opts.EmitUnpopulated {
+		fields = unpopulatedFieldRanger{m}
+	}
+	if typeURL != "" {
+		fields = typeURLFieldRanger{fields, typeURL}
+	}
+
+	var err error
+	order.RangeFields(fields, order.IndexNameFieldOrder, func(fd pref.FieldDescriptor, v pref.Value) bool {
+		name := fd.JSONName()
+		if e.opts.UseProtoNames {
+			name = fd.TextName()
+		}
+
+		if err = e.WriteName(name); err != nil {
+			return false
+		}
+		if err = e.marshalValue(v, fd); err != nil {
+			return false
+		}
+		return true
+	})
+	return err
+}
+
+// marshalValue marshals the given protoreflect.Value.
+func (e encoder) marshalValue(val pref.Value, fd pref.FieldDescriptor) error {
+	switch {
+	case fd.IsList():
+		return e.marshalList(val.List(), fd)
+	case fd.IsMap():
+		return e.marshalMap(val.Map(), fd)
+	default:
+		return e.marshalSingular(val, fd)
+	}
+}
+
+// marshalSingular marshals the given non-repeated field value. This includes
+// all scalar types, enums, messages, and groups.
+func (e encoder) marshalSingular(val pref.Value, fd pref.FieldDescriptor) error {
+	if !val.IsValid() {
+		e.WriteNull()
+		return nil
+	}
+
+	switch kind := fd.Kind(); kind {
+	case pref.BoolKind:
+		e.WriteBool(val.Bool())
+
+	case pref.StringKind:
+		if e.WriteString(val.String()) != nil {
+			return errors.InvalidUTF8(string(fd.FullName()))
+		}
+
+	case pref.Int32Kind, pref.Sint32Kind, pref.Sfixed32Kind:
+		e.WriteInt(val.Int())
+
+	case pref.Uint32Kind, pref.Fixed32Kind:
+		e.WriteUint(val.Uint())
+
+	case pref.Int64Kind, pref.Sint64Kind, pref.Uint64Kind,
+		pref.Sfixed64Kind, pref.Fixed64Kind:
+		// 64-bit integers are written out as JSON string.
+		e.WriteString(val.String())
+
+	case pref.FloatKind:
+		// Encoder.WriteFloat handles the special numbers NaN and infinites.
+		e.WriteFloat(val.Float(), 32)
+
+	case pref.DoubleKind:
+		// Encoder.WriteFloat handles the special numbers NaN and infinites.
+		e.WriteFloat(val.Float(), 64)
+
+	case pref.BytesKind:
+		e.WriteString(base64.StdEncoding.EncodeToString(val.Bytes()))
+
+	case pref.EnumKind:
+		if fd.Enum().FullName() == genid.NullValue_enum_fullname {
+			e.WriteNull()
+		} else {
+			desc := fd.Enum().Values().ByNumber(val.Enum())
+			if e.opts.UseEnumNumbers || desc == nil {
+				e.WriteInt(int64(val.Enum()))
+			} else {
+				e.WriteString(string(desc.Name()))
+			}
+		}
+
+	case pref.MessageKind, pref.GroupKind:
+		if err := e.marshalMessage(val.Message(), ""); err != nil {
+			return err
+		}
+
+	default:
+		panic(fmt.Sprintf("%v has unknown kind: %v", fd.FullName(), kind))
+	}
+	return nil
+}
+
+// marshalList marshals the given protoreflect.List.
+func (e encoder) marshalList(list pref.List, fd pref.FieldDescriptor) error {
+	e.StartArray()
+	defer e.EndArray()
+
+	for i := 0; i < list.Len(); i++ {
+		item := list.Get(i)
+		if err := e.marshalSingular(item, fd); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// marshalMap marshals given protoreflect.Map.
+func (e encoder) marshalMap(mmap pref.Map, fd pref.FieldDescriptor) error {
+	e.StartObject()
+	defer e.EndObject()
+
+	var err error
+	order.RangeEntries(mmap, order.GenericKeyOrder, func(k pref.MapKey, v pref.Value) bool {
+		if err = e.WriteName(k.String()); err != nil {
+			return false
+		}
+		if err = e.marshalSingular(v, fd.MapValue()); err != nil {
+			return false
+		}
+		return true
+	})
+	return err
+}
diff --git a/vendor/google.golang.org/protobuf/encoding/protojson/well_known_types.go b/vendor/google.golang.org/protobuf/encoding/protojson/well_known_types.go
new file mode 100644
index 0000000..72924a9
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/encoding/protojson/well_known_types.go
@@ -0,0 +1,889 @@
+// 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 protojson
+
+import (
+	"bytes"
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+	"time"
+
+	"google.golang.org/protobuf/internal/encoding/json"
+	"google.golang.org/protobuf/internal/errors"
+	"google.golang.org/protobuf/internal/genid"
+	"google.golang.org/protobuf/internal/strs"
+	"google.golang.org/protobuf/proto"
+	pref "google.golang.org/protobuf/reflect/protoreflect"
+)
+
+type marshalFunc func(encoder, pref.Message) error
+
+// wellKnownTypeMarshaler returns a marshal function if the message type
+// has specialized serialization behavior. It returns nil otherwise.
+func wellKnownTypeMarshaler(name pref.FullName) marshalFunc {
+	if name.Parent() == genid.GoogleProtobuf_package {
+		switch name.Name() {
+		case genid.Any_message_name:
+			return encoder.marshalAny
+		case genid.Timestamp_message_name:
+			return encoder.marshalTimestamp
+		case genid.Duration_message_name:
+			return encoder.marshalDuration
+		case genid.BoolValue_message_name,
+			genid.Int32Value_message_name,
+			genid.Int64Value_message_name,
+			genid.UInt32Value_message_name,
+			genid.UInt64Value_message_name,
+			genid.FloatValue_message_name,
+			genid.DoubleValue_message_name,
+			genid.StringValue_message_name,
+			genid.BytesValue_message_name:
+			return encoder.marshalWrapperType
+		case genid.Struct_message_name:
+			return encoder.marshalStruct
+		case genid.ListValue_message_name:
+			return encoder.marshalListValue
+		case genid.Value_message_name:
+			return encoder.marshalKnownValue
+		case genid.FieldMask_message_name:
+			return encoder.marshalFieldMask
+		case genid.Empty_message_name:
+			return encoder.marshalEmpty
+		}
+	}
+	return nil
+}
+
+type unmarshalFunc func(decoder, pref.Message) error
+
+// wellKnownTypeUnmarshaler returns a unmarshal function if the message type
+// has specialized serialization behavior. It returns nil otherwise.
+func wellKnownTypeUnmarshaler(name pref.FullName) unmarshalFunc {
+	if name.Parent() == genid.GoogleProtobuf_package {
+		switch name.Name() {
+		case genid.Any_message_name:
+			return decoder.unmarshalAny
+		case genid.Timestamp_message_name:
+			return decoder.unmarshalTimestamp
+		case genid.Duration_message_name:
+			return decoder.unmarshalDuration
+		case genid.BoolValue_message_name,
+			genid.Int32Value_message_name,
+			genid.Int64Value_message_name,
+			genid.UInt32Value_message_name,
+			genid.UInt64Value_message_name,
+			genid.FloatValue_message_name,
+			genid.DoubleValue_message_name,
+			genid.StringValue_message_name,
+			genid.BytesValue_message_name:
+			return decoder.unmarshalWrapperType
+		case genid.Struct_message_name:
+			return decoder.unmarshalStruct
+		case genid.ListValue_message_name:
+			return decoder.unmarshalListValue
+		case genid.Value_message_name:
+			return decoder.unmarshalKnownValue
+		case genid.FieldMask_message_name:
+			return decoder.unmarshalFieldMask
+		case genid.Empty_message_name:
+			return decoder.unmarshalEmpty
+		}
+	}
+	return nil
+}
+
+// The JSON representation of an Any message uses the regular representation of
+// the deserialized, embedded message, with an additional field `@type` which
+// contains the type URL. If the embedded message type is well-known and has a
+// custom JSON representation, that representation will be embedded adding a
+// field `value` which holds the custom JSON in addition to the `@type` field.
+
+func (e encoder) marshalAny(m pref.Message) error {
+	fds := m.Descriptor().Fields()
+	fdType := fds.ByNumber(genid.Any_TypeUrl_field_number)
+	fdValue := fds.ByNumber(genid.Any_Value_field_number)
+
+	if !m.Has(fdType) {
+		if !m.Has(fdValue) {
+			// If message is empty, marshal out empty JSON object.
+			e.StartObject()
+			e.EndObject()
+			return nil
+		} else {
+			// Return error if type_url field is not set, but value is set.
+			return errors.New("%s: %v is not set", genid.Any_message_fullname, genid.Any_TypeUrl_field_name)
+		}
+	}
+
+	typeVal := m.Get(fdType)
+	valueVal := m.Get(fdValue)
+
+	// Resolve the type in order to unmarshal value field.
+	typeURL := typeVal.String()
+	emt, err := e.opts.Resolver.FindMessageByURL(typeURL)
+	if err != nil {
+		return errors.New("%s: unable to resolve %q: %v", genid.Any_message_fullname, typeURL, err)
+	}
+
+	em := emt.New()
+	err = proto.UnmarshalOptions{
+		AllowPartial: true, // never check required fields inside an Any
+		Resolver:     e.opts.Resolver,
+	}.Unmarshal(valueVal.Bytes(), em.Interface())
+	if err != nil {
+		return errors.New("%s: unable to unmarshal %q: %v", genid.Any_message_fullname, typeURL, err)
+	}
+
+	// If type of value has custom JSON encoding, marshal out a field "value"
+	// with corresponding custom JSON encoding of the embedded message as a
+	// field.
+	if marshal := wellKnownTypeMarshaler(emt.Descriptor().FullName()); marshal != nil {
+		e.StartObject()
+		defer e.EndObject()
+
+		// Marshal out @type field.
+		e.WriteName("@type")
+		if err := e.WriteString(typeURL); err != nil {
+			return err
+		}
+
+		e.WriteName("value")
+		return marshal(e, em)
+	}
+
+	// Else, marshal out the embedded message's fields in this Any object.
+	if err := e.marshalMessage(em, typeURL); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (d decoder) unmarshalAny(m pref.Message) error {
+	// Peek to check for json.ObjectOpen to avoid advancing a read.
+	start, err := d.Peek()
+	if err != nil {
+		return err
+	}
+	if start.Kind() != json.ObjectOpen {
+		return d.unexpectedTokenError(start)
+	}
+
+	// Use another decoder to parse the unread bytes for @type field. This
+	// avoids advancing a read from current decoder because the current JSON
+	// object may contain the fields of the embedded type.
+	dec := decoder{d.Clone(), UnmarshalOptions{}}
+	tok, err := findTypeURL(dec)
+	switch err {
+	case errEmptyObject:
+		// An empty JSON object translates to an empty Any message.
+		d.Read() // Read json.ObjectOpen.
+		d.Read() // Read json.ObjectClose.
+		return nil
+
+	case errMissingType:
+		if d.opts.DiscardUnknown {
+			// Treat all fields as unknowns, similar to an empty object.
+			return d.skipJSONValue()
+		}
+		// Use start.Pos() for line position.
+		return d.newError(start.Pos(), err.Error())
+
+	default:
+		if err != nil {
+			return err
+		}
+	}
+
+	typeURL := tok.ParsedString()
+	emt, err := d.opts.Resolver.FindMessageByURL(typeURL)
+	if err != nil {
+		return d.newError(tok.Pos(), "unable to resolve %v: %q", tok.RawString(), err)
+	}
+
+	// Create new message for the embedded message type and unmarshal into it.
+	em := emt.New()
+	if unmarshal := wellKnownTypeUnmarshaler(emt.Descriptor().FullName()); unmarshal != nil {
+		// If embedded message is a custom type,
+		// unmarshal the JSON "value" field into it.
+		if err := d.unmarshalAnyValue(unmarshal, em); err != nil {
+			return err
+		}
+	} else {
+		// Else unmarshal the current JSON object into it.
+		if err := d.unmarshalMessage(em, true); err != nil {
+			return err
+		}
+	}
+	// Serialize the embedded message and assign the resulting bytes to the
+	// proto value field.
+	b, err := proto.MarshalOptions{
+		AllowPartial:  true, // No need to check required fields inside an Any.
+		Deterministic: true,
+	}.Marshal(em.Interface())
+	if err != nil {
+		return d.newError(start.Pos(), "error in marshaling Any.value field: %v", err)
+	}
+
+	fds := m.Descriptor().Fields()
+	fdType := fds.ByNumber(genid.Any_TypeUrl_field_number)
+	fdValue := fds.ByNumber(genid.Any_Value_field_number)
+
+	m.Set(fdType, pref.ValueOfString(typeURL))
+	m.Set(fdValue, pref.ValueOfBytes(b))
+	return nil
+}
+
+var errEmptyObject = fmt.Errorf(`empty object`)
+var errMissingType = fmt.Errorf(`missing "@type" field`)
+
+// findTypeURL returns the token for the "@type" field value from the given
+// JSON bytes. It is expected that the given bytes start with json.ObjectOpen.
+// It returns errEmptyObject if the JSON object is empty or errMissingType if
+// @type field does not exist. It returns other error if the @type field is not
+// valid or other decoding issues.
+func findTypeURL(d decoder) (json.Token, error) {
+	var typeURL string
+	var typeTok json.Token
+	numFields := 0
+	// Skip start object.
+	d.Read()
+
+Loop:
+	for {
+		tok, err := d.Read()
+		if err != nil {
+			return json.Token{}, err
+		}
+
+		switch tok.Kind() {
+		case json.ObjectClose:
+			if typeURL == "" {
+				// Did not find @type field.
+				if numFields > 0 {
+					return json.Token{}, errMissingType
+				}
+				return json.Token{}, errEmptyObject
+			}
+			break Loop
+
+		case json.Name:
+			numFields++
+			if tok.Name() != "@type" {
+				// Skip value.
+				if err := d.skipJSONValue(); err != nil {
+					return json.Token{}, err
+				}
+				continue
+			}
+
+			// Return error if this was previously set already.
+			if typeURL != "" {
+				return json.Token{}, d.newError(tok.Pos(), `duplicate "@type" field`)
+			}
+			// Read field value.
+			tok, err := d.Read()
+			if err != nil {
+				return json.Token{}, err
+			}
+			if tok.Kind() != json.String {
+				return json.Token{}, d.newError(tok.Pos(), `@type field value is not a string: %v`, tok.RawString())
+			}
+			typeURL = tok.ParsedString()
+			if typeURL == "" {
+				return json.Token{}, d.newError(tok.Pos(), `@type field contains empty value`)
+			}
+			typeTok = tok
+		}
+	}
+
+	return typeTok, nil
+}
+
+// skipJSONValue parses a JSON value (null, boolean, string, number, object and
+// array) in order to advance the read to the next JSON value. It relies on
+// the decoder returning an error if the types are not in valid sequence.
+func (d decoder) skipJSONValue() error {
+	tok, err := d.Read()
+	if err != nil {
+		return err
+	}
+	// Only need to continue reading for objects and arrays.
+	switch tok.Kind() {
+	case json.ObjectOpen:
+		for {
+			tok, err := d.Read()
+			if err != nil {
+				return err
+			}
+			switch tok.Kind() {
+			case json.ObjectClose:
+				return nil
+			case json.Name:
+				// Skip object field value.
+				if err := d.skipJSONValue(); err != nil {
+					return err
+				}
+			}
+		}
+
+	case json.ArrayOpen:
+		for {
+			tok, err := d.Peek()
+			if err != nil {
+				return err
+			}
+			switch tok.Kind() {
+			case json.ArrayClose:
+				d.Read()
+				return nil
+			default:
+				// Skip array item.
+				if err := d.skipJSONValue(); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// unmarshalAnyValue unmarshals the given custom-type message from the JSON
+// object's "value" field.
+func (d decoder) unmarshalAnyValue(unmarshal unmarshalFunc, m pref.Message) error {
+	// Skip ObjectOpen, and start reading the fields.
+	d.Read()
+
+	var found bool // Used for detecting duplicate "value".
+	for {
+		tok, err := d.Read()
+		if err != nil {
+			return err
+		}
+		switch tok.Kind() {
+		case json.ObjectClose:
+			if !found {
+				return d.newError(tok.Pos(), `missing "value" field`)
+			}
+			return nil
+
+		case json.Name:
+			switch tok.Name() {
+			case "@type":
+				// Skip the value as this was previously parsed already.
+				d.Read()
+
+			case "value":
+				if found {
+					return d.newError(tok.Pos(), `duplicate "value" field`)
+				}
+				// Unmarshal the field value into the given message.
+				if err := unmarshal(d, m); err != nil {
+					return err
+				}
+				found = true
+
+			default:
+				if d.opts.DiscardUnknown {
+					if err := d.skipJSONValue(); err != nil {
+						return err
+					}
+					continue
+				}
+				return d.newError(tok.Pos(), "unknown field %v", tok.RawString())
+			}
+		}
+	}
+}
+
+// Wrapper types are encoded as JSON primitives like string, number or boolean.
+
+func (e encoder) marshalWrapperType(m pref.Message) error {
+	fd := m.Descriptor().Fields().ByNumber(genid.WrapperValue_Value_field_number)
+	val := m.Get(fd)
+	return e.marshalSingular(val, fd)
+}
+
+func (d decoder) unmarshalWrapperType(m pref.Message) error {
+	fd := m.Descriptor().Fields().ByNumber(genid.WrapperValue_Value_field_number)
+	val, err := d.unmarshalScalar(fd)
+	if err != nil {
+		return err
+	}
+	m.Set(fd, val)
+	return nil
+}
+
+// The JSON representation for Empty is an empty JSON object.
+
+func (e encoder) marshalEmpty(pref.Message) error {
+	e.StartObject()
+	e.EndObject()
+	return nil
+}
+
+func (d decoder) unmarshalEmpty(pref.Message) error {
+	tok, err := d.Read()
+	if err != nil {
+		return err
+	}
+	if tok.Kind() != json.ObjectOpen {
+		return d.unexpectedTokenError(tok)
+	}
+
+	for {
+		tok, err := d.Read()
+		if err != nil {
+			return err
+		}
+		switch tok.Kind() {
+		case json.ObjectClose:
+			return nil
+
+		case json.Name:
+			if d.opts.DiscardUnknown {
+				if err := d.skipJSONValue(); err != nil {
+					return err
+				}
+				continue
+			}
+			return d.newError(tok.Pos(), "unknown field %v", tok.RawString())
+
+		default:
+			return d.unexpectedTokenError(tok)
+		}
+	}
+}
+
+// The JSON representation for Struct is a JSON object that contains the encoded
+// Struct.fields map and follows the serialization rules for a map.
+
+func (e encoder) marshalStruct(m pref.Message) error {
+	fd := m.Descriptor().Fields().ByNumber(genid.Struct_Fields_field_number)
+	return e.marshalMap(m.Get(fd).Map(), fd)
+}
+
+func (d decoder) unmarshalStruct(m pref.Message) error {
+	fd := m.Descriptor().Fields().ByNumber(genid.Struct_Fields_field_number)
+	return d.unmarshalMap(m.Mutable(fd).Map(), fd)
+}
+
+// The JSON representation for ListValue is JSON array that contains the encoded
+// ListValue.values repeated field and follows the serialization rules for a
+// repeated field.
+
+func (e encoder) marshalListValue(m pref.Message) error {
+	fd := m.Descriptor().Fields().ByNumber(genid.ListValue_Values_field_number)
+	return e.marshalList(m.Get(fd).List(), fd)
+}
+
+func (d decoder) unmarshalListValue(m pref.Message) error {
+	fd := m.Descriptor().Fields().ByNumber(genid.ListValue_Values_field_number)
+	return d.unmarshalList(m.Mutable(fd).List(), fd)
+}
+
+// The JSON representation for a Value is dependent on the oneof field that is
+// set. Each of the field in the oneof has its own custom serialization rule. A
+// Value message needs to be a oneof field set, else it is an error.
+
+func (e encoder) marshalKnownValue(m pref.Message) error {
+	od := m.Descriptor().Oneofs().ByName(genid.Value_Kind_oneof_name)
+	fd := m.WhichOneof(od)
+	if fd == nil {
+		return errors.New("%s: none of the oneof fields is set", genid.Value_message_fullname)
+	}
+	if fd.Number() == genid.Value_NumberValue_field_number {
+		if v := m.Get(fd).Float(); math.IsNaN(v) || math.IsInf(v, 0) {
+			return errors.New("%s: invalid %v value", genid.Value_NumberValue_field_fullname, v)
+		}
+	}
+	return e.marshalSingular(m.Get(fd), fd)
+}
+
+func (d decoder) unmarshalKnownValue(m pref.Message) error {
+	tok, err := d.Peek()
+	if err != nil {
+		return err
+	}
+
+	var fd pref.FieldDescriptor
+	var val pref.Value
+	switch tok.Kind() {
+	case json.Null:
+		d.Read()
+		fd = m.Descriptor().Fields().ByNumber(genid.Value_NullValue_field_number)
+		val = pref.ValueOfEnum(0)
+
+	case json.Bool:
+		tok, err := d.Read()
+		if err != nil {
+			return err
+		}
+		fd = m.Descriptor().Fields().ByNumber(genid.Value_BoolValue_field_number)
+		val = pref.ValueOfBool(tok.Bool())
+
+	case json.Number:
+		tok, err := d.Read()
+		if err != nil {
+			return err
+		}
+		fd = m.Descriptor().Fields().ByNumber(genid.Value_NumberValue_field_number)
+		var ok bool
+		val, ok = unmarshalFloat(tok, 64)
+		if !ok {
+			return d.newError(tok.Pos(), "invalid %v: %v", genid.Value_message_fullname, tok.RawString())
+		}
+
+	case json.String:
+		// A JSON string may have been encoded from the number_value field,
+		// e.g. "NaN", "Infinity", etc. Parsing a proto double type also allows
+		// for it to be in JSON string form. Given this custom encoding spec,
+		// however, there is no way to identify that and hence a JSON string is
+		// always assigned to the string_value field, which means that certain
+		// encoding cannot be parsed back to the same field.
+		tok, err := d.Read()
+		if err != nil {
+			return err
+		}
+		fd = m.Descriptor().Fields().ByNumber(genid.Value_StringValue_field_number)
+		val = pref.ValueOfString(tok.ParsedString())
+
+	case json.ObjectOpen:
+		fd = m.Descriptor().Fields().ByNumber(genid.Value_StructValue_field_number)
+		val = m.NewField(fd)
+		if err := d.unmarshalStruct(val.Message()); err != nil {
+			return err
+		}
+
+	case json.ArrayOpen:
+		fd = m.Descriptor().Fields().ByNumber(genid.Value_ListValue_field_number)
+		val = m.NewField(fd)
+		if err := d.unmarshalListValue(val.Message()); err != nil {
+			return err
+		}
+
+	default:
+		return d.newError(tok.Pos(), "invalid %v: %v", genid.Value_message_fullname, tok.RawString())
+	}
+
+	m.Set(fd, val)
+	return nil
+}
+
+// The JSON representation for a Duration is a JSON string that ends in the
+// suffix "s" (indicating seconds) and is preceded by the number of seconds,
+// with nanoseconds expressed as fractional seconds.
+//
+// Durations less than one second are represented with a 0 seconds field and a
+// positive or negative nanos field. For durations of one second or more, a
+// non-zero value for the nanos field must be of the same sign as the seconds
+// field.
+//
+// Duration.seconds must be from -315,576,000,000 to +315,576,000,000 inclusive.
+// Duration.nanos must be from -999,999,999 to +999,999,999 inclusive.
+
+const (
+	secondsInNanos       = 999999999
+	maxSecondsInDuration = 315576000000
+)
+
+func (e encoder) marshalDuration(m pref.Message) error {
+	fds := m.Descriptor().Fields()
+	fdSeconds := fds.ByNumber(genid.Duration_Seconds_field_number)
+	fdNanos := fds.ByNumber(genid.Duration_Nanos_field_number)
+
+	secsVal := m.Get(fdSeconds)
+	nanosVal := m.Get(fdNanos)
+	secs := secsVal.Int()
+	nanos := nanosVal.Int()
+	if secs < -maxSecondsInDuration || secs > maxSecondsInDuration {
+		return errors.New("%s: seconds out of range %v", genid.Duration_message_fullname, secs)
+	}
+	if nanos < -secondsInNanos || nanos > secondsInNanos {
+		return errors.New("%s: nanos out of range %v", genid.Duration_message_fullname, nanos)
+	}
+	if (secs > 0 && nanos < 0) || (secs < 0 && nanos > 0) {
+		return errors.New("%s: signs of seconds and nanos do not match", genid.Duration_message_fullname)
+	}
+	// Generated output always contains 0, 3, 6, or 9 fractional digits,
+	// depending on required precision, followed by the suffix "s".
+	var sign string
+	if secs < 0 || nanos < 0 {
+		sign, secs, nanos = "-", -1*secs, -1*nanos
+	}
+	x := fmt.Sprintf("%s%d.%09d", sign, secs, nanos)
+	x = strings.TrimSuffix(x, "000")
+	x = strings.TrimSuffix(x, "000")
+	x = strings.TrimSuffix(x, ".000")
+	e.WriteString(x + "s")
+	return nil
+}
+
+func (d decoder) unmarshalDuration(m pref.Message) error {
+	tok, err := d.Read()
+	if err != nil {
+		return err
+	}
+	if tok.Kind() != json.String {
+		return d.unexpectedTokenError(tok)
+	}
+
+	secs, nanos, ok := parseDuration(tok.ParsedString())
+	if !ok {
+		return d.newError(tok.Pos(), "invalid %v value %v", genid.Duration_message_fullname, tok.RawString())
+	}
+	// Validate seconds. No need to validate nanos because parseDuration would
+	// have covered that already.
+	if secs < -maxSecondsInDuration || secs > maxSecondsInDuration {
+		return d.newError(tok.Pos(), "%v value out of range: %v", genid.Duration_message_fullname, tok.RawString())
+	}
+
+	fds := m.Descriptor().Fields()
+	fdSeconds := fds.ByNumber(genid.Duration_Seconds_field_number)
+	fdNanos := fds.ByNumber(genid.Duration_Nanos_field_number)
+
+	m.Set(fdSeconds, pref.ValueOfInt64(secs))
+	m.Set(fdNanos, pref.ValueOfInt32(nanos))
+	return nil
+}
+
+// parseDuration parses the given input string for seconds and nanoseconds value
+// for the Duration JSON format. The format is a decimal number with a suffix
+// 's'. It can have optional plus/minus sign. There needs to be at least an
+// integer or fractional part. Fractional part is limited to 9 digits only for
+// nanoseconds precision, regardless of whether there are trailing zero digits.
+// Example values are 1s, 0.1s, 1.s, .1s, +1s, -1s, -.1s.
+func parseDuration(input string) (int64, int32, bool) {
+	b := []byte(input)
+	size := len(b)
+	if size < 2 {
+		return 0, 0, false
+	}
+	if b[size-1] != 's' {
+		return 0, 0, false
+	}
+	b = b[:size-1]
+
+	// Read optional plus/minus symbol.
+	var neg bool
+	switch b[0] {
+	case '-':
+		neg = true
+		b = b[1:]
+	case '+':
+		b = b[1:]
+	}
+	if len(b) == 0 {
+		return 0, 0, false
+	}
+
+	// Read the integer part.
+	var intp []byte
+	switch {
+	case b[0] == '0':
+		b = b[1:]
+
+	case '1' <= b[0] && b[0] <= '9':
+		intp = b[0:]
+		b = b[1:]
+		n := 1
+		for len(b) > 0 && '0' <= b[0] && b[0] <= '9' {
+			n++
+			b = b[1:]
+		}
+		intp = intp[:n]
+
+	case b[0] == '.':
+		// Continue below.
+
+	default:
+		return 0, 0, false
+	}
+
+	hasFrac := false
+	var frac [9]byte
+	if len(b) > 0 {
+		if b[0] != '.' {
+			return 0, 0, false
+		}
+		// Read the fractional part.
+		b = b[1:]
+		n := 0
+		for len(b) > 0 && n < 9 && '0' <= b[0] && b[0] <= '9' {
+			frac[n] = b[0]
+			n++
+			b = b[1:]
+		}
+		// It is not valid if there are more bytes left.
+		if len(b) > 0 {
+			return 0, 0, false
+		}
+		// Pad fractional part with 0s.
+		for i := n; i < 9; i++ {
+			frac[i] = '0'
+		}
+		hasFrac = true
+	}
+
+	var secs int64
+	if len(intp) > 0 {
+		var err error
+		secs, err = strconv.ParseInt(string(intp), 10, 64)
+		if err != nil {
+			return 0, 0, false
+		}
+	}
+
+	var nanos int64
+	if hasFrac {
+		nanob := bytes.TrimLeft(frac[:], "0")
+		if len(nanob) > 0 {
+			var err error
+			nanos, err = strconv.ParseInt(string(nanob), 10, 32)
+			if err != nil {
+				return 0, 0, false
+			}
+		}
+	}
+
+	if neg {
+		if secs > 0 {
+			secs = -secs
+		}
+		if nanos > 0 {
+			nanos = -nanos
+		}
+	}
+	return secs, int32(nanos), true
+}
+
+// The JSON representation for a Timestamp is a JSON string in the RFC 3339
+// format, i.e. "{year}-{month}-{day}T{hour}:{min}:{sec}[.{frac_sec}]Z" where
+// {year} is always expressed using four digits while {month}, {day}, {hour},
+// {min}, and {sec} are zero-padded to two digits each. The fractional seconds,
+// which can go up to 9 digits, up to 1 nanosecond resolution, is optional. The
+// "Z" suffix indicates the timezone ("UTC"); the timezone is required. Encoding
+// should always use UTC (as indicated by "Z") and a decoder should be able to
+// accept both UTC and other timezones (as indicated by an offset).
+//
+// Timestamp.seconds must be from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59Z
+// inclusive.
+// Timestamp.nanos must be from 0 to 999,999,999 inclusive.
+
+const (
+	maxTimestampSeconds = 253402300799
+	minTimestampSeconds = -62135596800
+)
+
+func (e encoder) marshalTimestamp(m pref.Message) error {
+	fds := m.Descriptor().Fields()
+	fdSeconds := fds.ByNumber(genid.Timestamp_Seconds_field_number)
+	fdNanos := fds.ByNumber(genid.Timestamp_Nanos_field_number)
+
+	secsVal := m.Get(fdSeconds)
+	nanosVal := m.Get(fdNanos)
+	secs := secsVal.Int()
+	nanos := nanosVal.Int()
+	if secs < minTimestampSeconds || secs > maxTimestampSeconds {
+		return errors.New("%s: seconds out of range %v", genid.Timestamp_message_fullname, secs)
+	}
+	if nanos < 0 || nanos > secondsInNanos {
+		return errors.New("%s: nanos out of range %v", genid.Timestamp_message_fullname, nanos)
+	}
+	// Uses RFC 3339, where generated output will be Z-normalized and uses 0, 3,
+	// 6 or 9 fractional digits.
+	t := time.Unix(secs, nanos).UTC()
+	x := t.Format("2006-01-02T15:04:05.000000000")
+	x = strings.TrimSuffix(x, "000")
+	x = strings.TrimSuffix(x, "000")
+	x = strings.TrimSuffix(x, ".000")
+	e.WriteString(x + "Z")
+	return nil
+}
+
+func (d decoder) unmarshalTimestamp(m pref.Message) error {
+	tok, err := d.Read()
+	if err != nil {
+		return err
+	}
+	if tok.Kind() != json.String {
+		return d.unexpectedTokenError(tok)
+	}
+
+	t, err := time.Parse(time.RFC3339Nano, tok.ParsedString())
+	if err != nil {
+		return d.newError(tok.Pos(), "invalid %v value %v", genid.Timestamp_message_fullname, tok.RawString())
+	}
+	// Validate seconds. No need to validate nanos because time.Parse would have
+	// covered that already.
+	secs := t.Unix()
+	if secs < minTimestampSeconds || secs > maxTimestampSeconds {
+		return d.newError(tok.Pos(), "%v value out of range: %v", genid.Timestamp_message_fullname, tok.RawString())
+	}
+
+	fds := m.Descriptor().Fields()
+	fdSeconds := fds.ByNumber(genid.Timestamp_Seconds_field_number)
+	fdNanos := fds.ByNumber(genid.Timestamp_Nanos_field_number)
+
+	m.Set(fdSeconds, pref.ValueOfInt64(secs))
+	m.Set(fdNanos, pref.ValueOfInt32(int32(t.Nanosecond())))
+	return nil
+}
+
+// The JSON representation for a FieldMask is a JSON string where paths are
+// separated by a comma. Fields name in each path are converted to/from
+// lower-camel naming conventions. Encoding should fail if the path name would
+// end up differently after a round-trip.
+
+func (e encoder) marshalFieldMask(m pref.Message) error {
+	fd := m.Descriptor().Fields().ByNumber(genid.FieldMask_Paths_field_number)
+	list := m.Get(fd).List()
+	paths := make([]string, 0, list.Len())
+
+	for i := 0; i < list.Len(); i++ {
+		s := list.Get(i).String()
+		if !pref.FullName(s).IsValid() {
+			return errors.New("%s contains invalid path: %q", genid.FieldMask_Paths_field_fullname, s)
+		}
+		// Return error if conversion to camelCase is not reversible.
+		cc := strs.JSONCamelCase(s)
+		if s != strs.JSONSnakeCase(cc) {
+			return errors.New("%s contains irreversible value %q", genid.FieldMask_Paths_field_fullname, s)
+		}
+		paths = append(paths, cc)
+	}
+
+	e.WriteString(strings.Join(paths, ","))
+	return nil
+}
+
+func (d decoder) unmarshalFieldMask(m pref.Message) error {
+	tok, err := d.Read()
+	if err != nil {
+		return err
+	}
+	if tok.Kind() != json.String {
+		return d.unexpectedTokenError(tok)
+	}
+	str := strings.TrimSpace(tok.ParsedString())
+	if str == "" {
+		return nil
+	}
+	paths := strings.Split(str, ",")
+
+	fd := m.Descriptor().Fields().ByNumber(genid.FieldMask_Paths_field_number)
+	list := m.Mutable(fd).List()
+
+	for _, s0 := range paths {
+		s := strs.JSONSnakeCase(s0)
+		if strings.Contains(s0, "_") || !pref.FullName(s).IsValid() {
+			return d.newError(tok.Pos(), "%v contains invalid path: %q", genid.FieldMask_Paths_field_fullname, s0)
+		}
+		list.Append(pref.ValueOfString(s))
+	}
+	return nil
+}