diff --git a/vendor/google.golang.org/protobuf/internal/impl/codec_message.go b/vendor/google.golang.org/protobuf/internal/impl/codec_message.go
new file mode 100644
index 0000000..cd40527
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/impl/codec_message.go
@@ -0,0 +1,217 @@
+// 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 impl
+
+import (
+	"fmt"
+	"reflect"
+	"sort"
+
+	"google.golang.org/protobuf/encoding/protowire"
+	"google.golang.org/protobuf/internal/encoding/messageset"
+	"google.golang.org/protobuf/internal/order"
+	pref "google.golang.org/protobuf/reflect/protoreflect"
+	piface "google.golang.org/protobuf/runtime/protoiface"
+)
+
+// coderMessageInfo contains per-message information used by the fast-path functions.
+// This is a different type from MessageInfo to keep MessageInfo as general-purpose as
+// possible.
+type coderMessageInfo struct {
+	methods piface.Methods
+
+	orderedCoderFields []*coderFieldInfo
+	denseCoderFields   []*coderFieldInfo
+	coderFields        map[protowire.Number]*coderFieldInfo
+	sizecacheOffset    offset
+	unknownOffset      offset
+	unknownPtrKind     bool
+	extensionOffset    offset
+	needsInitCheck     bool
+	isMessageSet       bool
+	numRequiredFields  uint8
+}
+
+type coderFieldInfo struct {
+	funcs      pointerCoderFuncs // fast-path per-field functions
+	mi         *MessageInfo      // field's message
+	ft         reflect.Type
+	validation validationInfo   // information used by message validation
+	num        pref.FieldNumber // field number
+	offset     offset           // struct field offset
+	wiretag    uint64           // field tag (number + wire type)
+	tagsize    int              // size of the varint-encoded tag
+	isPointer  bool             // true if IsNil may be called on the struct field
+	isRequired bool             // true if field is required
+}
+
+func (mi *MessageInfo) makeCoderMethods(t reflect.Type, si structInfo) {
+	mi.sizecacheOffset = invalidOffset
+	mi.unknownOffset = invalidOffset
+	mi.extensionOffset = invalidOffset
+
+	if si.sizecacheOffset.IsValid() && si.sizecacheType == sizecacheType {
+		mi.sizecacheOffset = si.sizecacheOffset
+	}
+	if si.unknownOffset.IsValid() && (si.unknownType == unknownFieldsAType || si.unknownType == unknownFieldsBType) {
+		mi.unknownOffset = si.unknownOffset
+		mi.unknownPtrKind = si.unknownType.Kind() == reflect.Ptr
+	}
+	if si.extensionOffset.IsValid() && si.extensionType == extensionFieldsType {
+		mi.extensionOffset = si.extensionOffset
+	}
+
+	mi.coderFields = make(map[protowire.Number]*coderFieldInfo)
+	fields := mi.Desc.Fields()
+	preallocFields := make([]coderFieldInfo, fields.Len())
+	for i := 0; i < fields.Len(); i++ {
+		fd := fields.Get(i)
+
+		fs := si.fieldsByNumber[fd.Number()]
+		isOneof := fd.ContainingOneof() != nil && !fd.ContainingOneof().IsSynthetic()
+		if isOneof {
+			fs = si.oneofsByName[fd.ContainingOneof().Name()]
+		}
+		ft := fs.Type
+		var wiretag uint64
+		if !fd.IsPacked() {
+			wiretag = protowire.EncodeTag(fd.Number(), wireTypes[fd.Kind()])
+		} else {
+			wiretag = protowire.EncodeTag(fd.Number(), protowire.BytesType)
+		}
+		var fieldOffset offset
+		var funcs pointerCoderFuncs
+		var childMessage *MessageInfo
+		switch {
+		case ft == nil:
+			// This never occurs for generated message types.
+			// It implies that a hand-crafted type has missing Go fields
+			// for specific protobuf message fields.
+			funcs = pointerCoderFuncs{
+				size: func(p pointer, f *coderFieldInfo, opts marshalOptions) int {
+					return 0
+				},
+				marshal: func(b []byte, p pointer, f *coderFieldInfo, opts marshalOptions) ([]byte, error) {
+					return nil, nil
+				},
+				unmarshal: func(b []byte, p pointer, wtyp protowire.Type, f *coderFieldInfo, opts unmarshalOptions) (unmarshalOutput, error) {
+					panic("missing Go struct field for " + string(fd.FullName()))
+				},
+				isInit: func(p pointer, f *coderFieldInfo) error {
+					panic("missing Go struct field for " + string(fd.FullName()))
+				},
+				merge: func(dst, src pointer, f *coderFieldInfo, opts mergeOptions) {
+					panic("missing Go struct field for " + string(fd.FullName()))
+				},
+			}
+		case isOneof:
+			fieldOffset = offsetOf(fs, mi.Exporter)
+		case fd.IsWeak():
+			fieldOffset = si.weakOffset
+			funcs = makeWeakMessageFieldCoder(fd)
+		default:
+			fieldOffset = offsetOf(fs, mi.Exporter)
+			childMessage, funcs = fieldCoder(fd, ft)
+		}
+		cf := &preallocFields[i]
+		*cf = coderFieldInfo{
+			num:        fd.Number(),
+			offset:     fieldOffset,
+			wiretag:    wiretag,
+			ft:         ft,
+			tagsize:    protowire.SizeVarint(wiretag),
+			funcs:      funcs,
+			mi:         childMessage,
+			validation: newFieldValidationInfo(mi, si, fd, ft),
+			isPointer:  fd.Cardinality() == pref.Repeated || fd.HasPresence(),
+			isRequired: fd.Cardinality() == pref.Required,
+		}
+		mi.orderedCoderFields = append(mi.orderedCoderFields, cf)
+		mi.coderFields[cf.num] = cf
+	}
+	for i, oneofs := 0, mi.Desc.Oneofs(); i < oneofs.Len(); i++ {
+		if od := oneofs.Get(i); !od.IsSynthetic() {
+			mi.initOneofFieldCoders(od, si)
+		}
+	}
+	if messageset.IsMessageSet(mi.Desc) {
+		if !mi.extensionOffset.IsValid() {
+			panic(fmt.Sprintf("%v: MessageSet with no extensions field", mi.Desc.FullName()))
+		}
+		if !mi.unknownOffset.IsValid() {
+			panic(fmt.Sprintf("%v: MessageSet with no unknown field", mi.Desc.FullName()))
+		}
+		mi.isMessageSet = true
+	}
+	sort.Slice(mi.orderedCoderFields, func(i, j int) bool {
+		return mi.orderedCoderFields[i].num < mi.orderedCoderFields[j].num
+	})
+
+	var maxDense pref.FieldNumber
+	for _, cf := range mi.orderedCoderFields {
+		if cf.num >= 16 && cf.num >= 2*maxDense {
+			break
+		}
+		maxDense = cf.num
+	}
+	mi.denseCoderFields = make([]*coderFieldInfo, maxDense+1)
+	for _, cf := range mi.orderedCoderFields {
+		if int(cf.num) >= len(mi.denseCoderFields) {
+			break
+		}
+		mi.denseCoderFields[cf.num] = cf
+	}
+
+	// To preserve compatibility with historic wire output, marshal oneofs last.
+	if mi.Desc.Oneofs().Len() > 0 {
+		sort.Slice(mi.orderedCoderFields, func(i, j int) bool {
+			fi := fields.ByNumber(mi.orderedCoderFields[i].num)
+			fj := fields.ByNumber(mi.orderedCoderFields[j].num)
+			return order.LegacyFieldOrder(fi, fj)
+		})
+	}
+
+	mi.needsInitCheck = needsInitCheck(mi.Desc)
+	if mi.methods.Marshal == nil && mi.methods.Size == nil {
+		mi.methods.Flags |= piface.SupportMarshalDeterministic
+		mi.methods.Marshal = mi.marshal
+		mi.methods.Size = mi.size
+	}
+	if mi.methods.Unmarshal == nil {
+		mi.methods.Flags |= piface.SupportUnmarshalDiscardUnknown
+		mi.methods.Unmarshal = mi.unmarshal
+	}
+	if mi.methods.CheckInitialized == nil {
+		mi.methods.CheckInitialized = mi.checkInitialized
+	}
+	if mi.methods.Merge == nil {
+		mi.methods.Merge = mi.merge
+	}
+}
+
+// getUnknownBytes returns a *[]byte for the unknown fields.
+// It is the caller's responsibility to check whether the pointer is nil.
+// This function is specially designed to be inlineable.
+func (mi *MessageInfo) getUnknownBytes(p pointer) *[]byte {
+	if mi.unknownPtrKind {
+		return *p.Apply(mi.unknownOffset).BytesPtr()
+	} else {
+		return p.Apply(mi.unknownOffset).Bytes()
+	}
+}
+
+// mutableUnknownBytes returns a *[]byte for the unknown fields.
+// The returned pointer is guaranteed to not be nil.
+func (mi *MessageInfo) mutableUnknownBytes(p pointer) *[]byte {
+	if mi.unknownPtrKind {
+		bp := p.Apply(mi.unknownOffset).BytesPtr()
+		if *bp == nil {
+			*bp = new([]byte)
+		}
+		return *bp
+	} else {
+		return p.Apply(mi.unknownOffset).Bytes()
+	}
+}