diff --git a/vendor/google.golang.org/protobuf/proto/encode.go b/vendor/google.golang.org/protobuf/proto/encode.go
new file mode 100644
index 0000000..456bfda
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/proto/encode.go
@@ -0,0 +1,343 @@
+// 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 (
+	"sort"
+
+	"google.golang.org/protobuf/encoding/protowire"
+	"google.golang.org/protobuf/internal/encoding/messageset"
+	"google.golang.org/protobuf/internal/fieldsort"
+	"google.golang.org/protobuf/internal/mapsort"
+	"google.golang.org/protobuf/internal/pragma"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/runtime/protoiface"
+)
+
+// MarshalOptions configures the marshaler.
+//
+// Example usage:
+//   b, err := MarshalOptions{Deterministic: true}.Marshal(m)
+type MarshalOptions struct {
+	pragma.NoUnkeyedLiterals
+
+	// AllowPartial allows messages that have missing required fields to marshal
+	// without returning an error. If AllowPartial is false (the default),
+	// Marshal will return an error if there are any missing required fields.
+	AllowPartial bool
+
+	// Deterministic controls whether the same message will always be
+	// serialized to the same bytes within the same binary.
+	//
+	// Setting this option guarantees that repeated serialization of
+	// the same message will return the same bytes, and that different
+	// processes of the same binary (which may be executing on different
+	// machines) will serialize equal messages to the same bytes.
+	// It has no effect on the resulting size of the encoded message compared
+	// to a non-deterministic marshal.
+	//
+	// 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.) must 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.
+	Deterministic bool
+
+	// UseCachedSize indicates that the result of a previous Size call
+	// may be reused.
+	//
+	// Setting this option asserts that:
+	//
+	// 1. Size has previously been called on this message with identical
+	// options (except for UseCachedSize itself).
+	//
+	// 2. The message and all its submessages have not changed in any
+	// way since the Size call.
+	//
+	// If either of these invariants is violated,
+	// the results are undefined and may include panics or corrupted output.
+	//
+	// Implementations MAY take this option into account to provide
+	// better performance, but there is no guarantee that they will do so.
+	// There is absolutely no guarantee that Size followed by Marshal with
+	// UseCachedSize set will perform equivalently to Marshal alone.
+	UseCachedSize bool
+}
+
+// Marshal returns the wire-format encoding of m.
+func Marshal(m Message) ([]byte, error) {
+	// Treat nil message interface as an empty message; nothing to output.
+	if m == nil {
+		return nil, nil
+	}
+
+	out, err := MarshalOptions{}.marshal(nil, m.ProtoReflect())
+	if len(out.Buf) == 0 && err == nil {
+		out.Buf = emptyBytesForMessage(m)
+	}
+	return out.Buf, err
+}
+
+// Marshal returns the wire-format encoding of m.
+func (o MarshalOptions) Marshal(m Message) ([]byte, error) {
+	// Treat nil message interface as an empty message; nothing to output.
+	if m == nil {
+		return nil, nil
+	}
+
+	out, err := o.marshal(nil, m.ProtoReflect())
+	if len(out.Buf) == 0 && err == nil {
+		out.Buf = emptyBytesForMessage(m)
+	}
+	return out.Buf, err
+}
+
+// emptyBytesForMessage returns a nil buffer if and only if m is invalid,
+// otherwise it returns a non-nil empty buffer.
+//
+// This is to assist the edge-case where user-code does the following:
+//	m1.OptionalBytes, _ = proto.Marshal(m2)
+// where they expect the proto2 "optional_bytes" field to be populated
+// if any only if m2 is a valid message.
+func emptyBytesForMessage(m Message) []byte {
+	if m == nil || !m.ProtoReflect().IsValid() {
+		return nil
+	}
+	return emptyBuf[:]
+}
+
+// MarshalAppend appends the wire-format encoding of m to b,
+// returning the result.
+func (o MarshalOptions) MarshalAppend(b []byte, m Message) ([]byte, error) {
+	// Treat nil message interface as an empty message; nothing to append.
+	if m == nil {
+		return b, nil
+	}
+
+	out, err := o.marshal(b, m.ProtoReflect())
+	return out.Buf, err
+}
+
+// MarshalState returns the wire-format encoding of a message.
+//
+// This method permits fine-grained control over the marshaler.
+// Most users should use Marshal instead.
+func (o MarshalOptions) MarshalState(in protoiface.MarshalInput) (protoiface.MarshalOutput, error) {
+	return o.marshal(in.Buf, in.Message)
+}
+
+func (o MarshalOptions) marshal(b []byte, m protoreflect.Message) (out protoiface.MarshalOutput, err error) {
+	allowPartial := o.AllowPartial
+	o.AllowPartial = true
+	if methods := protoMethods(m); methods != nil && methods.Marshal != nil &&
+		!(o.Deterministic && methods.Flags&protoiface.SupportMarshalDeterministic == 0) {
+		in := protoiface.MarshalInput{
+			Message: m,
+			Buf:     b,
+		}
+		if o.Deterministic {
+			in.Flags |= protoiface.MarshalDeterministic
+		}
+		if o.UseCachedSize {
+			in.Flags |= protoiface.MarshalUseCachedSize
+		}
+		if methods.Size != nil {
+			sout := methods.Size(protoiface.SizeInput{
+				Message: m,
+				Flags:   in.Flags,
+			})
+			if cap(b) < len(b)+sout.Size {
+				in.Buf = make([]byte, len(b), growcap(cap(b), len(b)+sout.Size))
+				copy(in.Buf, b)
+			}
+			in.Flags |= protoiface.MarshalUseCachedSize
+		}
+		out, err = methods.Marshal(in)
+	} else {
+		out.Buf, err = o.marshalMessageSlow(b, m)
+	}
+	if err != nil {
+		return out, err
+	}
+	if allowPartial {
+		return out, nil
+	}
+	return out, checkInitialized(m)
+}
+
+func (o MarshalOptions) marshalMessage(b []byte, m protoreflect.Message) ([]byte, error) {
+	out, err := o.marshal(b, m)
+	return out.Buf, err
+}
+
+// growcap scales up the capacity of a slice.
+//
+// Given a slice with a current capacity of oldcap and a desired
+// capacity of wantcap, growcap returns a new capacity >= wantcap.
+//
+// The algorithm is mostly identical to the one used by append as of Go 1.14.
+func growcap(oldcap, wantcap int) (newcap int) {
+	if wantcap > oldcap*2 {
+		newcap = wantcap
+	} else if oldcap < 1024 {
+		// The Go 1.14 runtime takes this case when len(s) < 1024,
+		// not when cap(s) < 1024. The difference doesn't seem
+		// significant here.
+		newcap = oldcap * 2
+	} else {
+		newcap = oldcap
+		for 0 < newcap && newcap < wantcap {
+			newcap += newcap / 4
+		}
+		if newcap <= 0 {
+			newcap = wantcap
+		}
+	}
+	return newcap
+}
+
+func (o MarshalOptions) marshalMessageSlow(b []byte, m protoreflect.Message) ([]byte, error) {
+	if messageset.IsMessageSet(m.Descriptor()) {
+		return marshalMessageSet(b, m, o)
+	}
+	// There are many choices for what order we visit fields in. The default one here
+	// is chosen for reasonable efficiency and simplicity given the protoreflect API.
+	// It is not deterministic, since Message.Range does not return fields in any
+	// defined order.
+	//
+	// When using deterministic serialization, we sort the known fields.
+	var err error
+	o.rangeFields(m, func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
+		b, err = o.marshalField(b, fd, v)
+		return err == nil
+	})
+	if err != nil {
+		return b, err
+	}
+	b = append(b, m.GetUnknown()...)
+	return b, nil
+}
+
+// rangeFields visits fields in a defined order when deterministic serialization is enabled.
+func (o MarshalOptions) rangeFields(m protoreflect.Message, f func(protoreflect.FieldDescriptor, protoreflect.Value) bool) {
+	if !o.Deterministic {
+		m.Range(f)
+		return
+	}
+	var fds []protoreflect.FieldDescriptor
+	m.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
+		fds = append(fds, fd)
+		return true
+	})
+	sort.Slice(fds, func(a, b int) bool {
+		return fieldsort.Less(fds[a], fds[b])
+	})
+	for _, fd := range fds {
+		if !f(fd, m.Get(fd)) {
+			break
+		}
+	}
+}
+
+func (o MarshalOptions) marshalField(b []byte, fd protoreflect.FieldDescriptor, value protoreflect.Value) ([]byte, error) {
+	switch {
+	case fd.IsList():
+		return o.marshalList(b, fd, value.List())
+	case fd.IsMap():
+		return o.marshalMap(b, fd, value.Map())
+	default:
+		b = protowire.AppendTag(b, fd.Number(), wireTypes[fd.Kind()])
+		return o.marshalSingular(b, fd, value)
+	}
+}
+
+func (o MarshalOptions) marshalList(b []byte, fd protoreflect.FieldDescriptor, list protoreflect.List) ([]byte, error) {
+	if fd.IsPacked() && list.Len() > 0 {
+		b = protowire.AppendTag(b, fd.Number(), protowire.BytesType)
+		b, pos := appendSpeculativeLength(b)
+		for i, llen := 0, list.Len(); i < llen; i++ {
+			var err error
+			b, err = o.marshalSingular(b, fd, list.Get(i))
+			if err != nil {
+				return b, err
+			}
+		}
+		b = finishSpeculativeLength(b, pos)
+		return b, nil
+	}
+
+	kind := fd.Kind()
+	for i, llen := 0, list.Len(); i < llen; i++ {
+		var err error
+		b = protowire.AppendTag(b, fd.Number(), wireTypes[kind])
+		b, err = o.marshalSingular(b, fd, list.Get(i))
+		if err != nil {
+			return b, err
+		}
+	}
+	return b, nil
+}
+
+func (o MarshalOptions) marshalMap(b []byte, fd protoreflect.FieldDescriptor, mapv protoreflect.Map) ([]byte, error) {
+	keyf := fd.MapKey()
+	valf := fd.MapValue()
+	var err error
+	o.rangeMap(mapv, keyf.Kind(), func(key protoreflect.MapKey, value protoreflect.Value) bool {
+		b = protowire.AppendTag(b, fd.Number(), protowire.BytesType)
+		var pos int
+		b, pos = appendSpeculativeLength(b)
+
+		b, err = o.marshalField(b, keyf, key.Value())
+		if err != nil {
+			return false
+		}
+		b, err = o.marshalField(b, valf, value)
+		if err != nil {
+			return false
+		}
+		b = finishSpeculativeLength(b, pos)
+		return true
+	})
+	return b, err
+}
+
+func (o MarshalOptions) rangeMap(mapv protoreflect.Map, kind protoreflect.Kind, f func(protoreflect.MapKey, protoreflect.Value) bool) {
+	if !o.Deterministic {
+		mapv.Range(f)
+		return
+	}
+	mapsort.Range(mapv, kind, f)
+}
+
+// When encoding length-prefixed fields, we speculatively set aside some number of bytes
+// for the length, encode the data, and then encode the length (shifting the data if necessary
+// to make room).
+const speculativeLength = 1
+
+func appendSpeculativeLength(b []byte) ([]byte, int) {
+	pos := len(b)
+	b = append(b, "\x00\x00\x00\x00"[:speculativeLength]...)
+	return b, pos
+}
+
+func finishSpeculativeLength(b []byte, pos int) []byte {
+	mlen := len(b) - pos - speculativeLength
+	msiz := protowire.SizeVarint(uint64(mlen))
+	if msiz != speculativeLength {
+		for i := 0; i < msiz-speculativeLength; i++ {
+			b = append(b, 0)
+		}
+		copy(b[pos+msiz:], b[pos+speculativeLength:])
+		b = b[:pos+msiz+mlen]
+	}
+	protowire.AppendVarint(b[:pos], uint64(mlen))
+	return b
+}