diff --git a/vendor/go.etcd.io/etcd/etcdserver/api/rafthttp/msgappv2_codec.go b/vendor/go.etcd.io/etcd/etcdserver/api/rafthttp/msgappv2_codec.go
new file mode 100644
index 0000000..1fa36de
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/etcdserver/api/rafthttp/msgappv2_codec.go
@@ -0,0 +1,248 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rafthttp
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"time"
+
+	stats "go.etcd.io/etcd/etcdserver/api/v2stats"
+	"go.etcd.io/etcd/pkg/pbutil"
+	"go.etcd.io/etcd/pkg/types"
+	"go.etcd.io/etcd/raft/raftpb"
+)
+
+const (
+	msgTypeLinkHeartbeat uint8 = 0
+	msgTypeAppEntries    uint8 = 1
+	msgTypeApp           uint8 = 2
+
+	msgAppV2BufSize = 1024 * 1024
+)
+
+// msgappv2 stream sends three types of message: linkHeartbeatMessage,
+// AppEntries and MsgApp. AppEntries is the MsgApp that is sent in
+// replicate state in raft, whose index and term are fully predictable.
+//
+// Data format of linkHeartbeatMessage:
+// | offset | bytes | description |
+// +--------+-------+-------------+
+// | 0      | 1     | \x00        |
+//
+// Data format of AppEntries:
+// | offset | bytes | description |
+// +--------+-------+-------------+
+// | 0      | 1     | \x01        |
+// | 1      | 8     | length of entries |
+// | 9      | 8     | length of first entry |
+// | 17     | n1    | first entry |
+// ...
+// | x      | 8     | length of k-th entry data |
+// | x+8    | nk    | k-th entry data |
+// | x+8+nk | 8     | commit index |
+//
+// Data format of MsgApp:
+// | offset | bytes | description |
+// +--------+-------+-------------+
+// | 0      | 1     | \x02        |
+// | 1      | 8     | length of encoded message |
+// | 9      | n     | encoded message |
+type msgAppV2Encoder struct {
+	w  io.Writer
+	fs *stats.FollowerStats
+
+	term      uint64
+	index     uint64
+	buf       []byte
+	uint64buf []byte
+	uint8buf  []byte
+}
+
+func newMsgAppV2Encoder(w io.Writer, fs *stats.FollowerStats) *msgAppV2Encoder {
+	return &msgAppV2Encoder{
+		w:         w,
+		fs:        fs,
+		buf:       make([]byte, msgAppV2BufSize),
+		uint64buf: make([]byte, 8),
+		uint8buf:  make([]byte, 1),
+	}
+}
+
+func (enc *msgAppV2Encoder) encode(m *raftpb.Message) error {
+	start := time.Now()
+	switch {
+	case isLinkHeartbeatMessage(m):
+		enc.uint8buf[0] = msgTypeLinkHeartbeat
+		if _, err := enc.w.Write(enc.uint8buf); err != nil {
+			return err
+		}
+	case enc.index == m.Index && enc.term == m.LogTerm && m.LogTerm == m.Term:
+		enc.uint8buf[0] = msgTypeAppEntries
+		if _, err := enc.w.Write(enc.uint8buf); err != nil {
+			return err
+		}
+		// write length of entries
+		binary.BigEndian.PutUint64(enc.uint64buf, uint64(len(m.Entries)))
+		if _, err := enc.w.Write(enc.uint64buf); err != nil {
+			return err
+		}
+		for i := 0; i < len(m.Entries); i++ {
+			// write length of entry
+			binary.BigEndian.PutUint64(enc.uint64buf, uint64(m.Entries[i].Size()))
+			if _, err := enc.w.Write(enc.uint64buf); err != nil {
+				return err
+			}
+			if n := m.Entries[i].Size(); n < msgAppV2BufSize {
+				if _, err := m.Entries[i].MarshalTo(enc.buf); err != nil {
+					return err
+				}
+				if _, err := enc.w.Write(enc.buf[:n]); err != nil {
+					return err
+				}
+			} else {
+				if _, err := enc.w.Write(pbutil.MustMarshal(&m.Entries[i])); err != nil {
+					return err
+				}
+			}
+			enc.index++
+		}
+		// write commit index
+		binary.BigEndian.PutUint64(enc.uint64buf, m.Commit)
+		if _, err := enc.w.Write(enc.uint64buf); err != nil {
+			return err
+		}
+		enc.fs.Succ(time.Since(start))
+	default:
+		if err := binary.Write(enc.w, binary.BigEndian, msgTypeApp); err != nil {
+			return err
+		}
+		// write size of message
+		if err := binary.Write(enc.w, binary.BigEndian, uint64(m.Size())); err != nil {
+			return err
+		}
+		// write message
+		if _, err := enc.w.Write(pbutil.MustMarshal(m)); err != nil {
+			return err
+		}
+
+		enc.term = m.Term
+		enc.index = m.Index
+		if l := len(m.Entries); l > 0 {
+			enc.index = m.Entries[l-1].Index
+		}
+		enc.fs.Succ(time.Since(start))
+	}
+	return nil
+}
+
+type msgAppV2Decoder struct {
+	r             io.Reader
+	local, remote types.ID
+
+	term      uint64
+	index     uint64
+	buf       []byte
+	uint64buf []byte
+	uint8buf  []byte
+}
+
+func newMsgAppV2Decoder(r io.Reader, local, remote types.ID) *msgAppV2Decoder {
+	return &msgAppV2Decoder{
+		r:         r,
+		local:     local,
+		remote:    remote,
+		buf:       make([]byte, msgAppV2BufSize),
+		uint64buf: make([]byte, 8),
+		uint8buf:  make([]byte, 1),
+	}
+}
+
+func (dec *msgAppV2Decoder) decode() (raftpb.Message, error) {
+	var (
+		m   raftpb.Message
+		typ uint8
+	)
+	if _, err := io.ReadFull(dec.r, dec.uint8buf); err != nil {
+		return m, err
+	}
+	typ = dec.uint8buf[0]
+	switch typ {
+	case msgTypeLinkHeartbeat:
+		return linkHeartbeatMessage, nil
+	case msgTypeAppEntries:
+		m = raftpb.Message{
+			Type:    raftpb.MsgApp,
+			From:    uint64(dec.remote),
+			To:      uint64(dec.local),
+			Term:    dec.term,
+			LogTerm: dec.term,
+			Index:   dec.index,
+		}
+
+		// decode entries
+		if _, err := io.ReadFull(dec.r, dec.uint64buf); err != nil {
+			return m, err
+		}
+		l := binary.BigEndian.Uint64(dec.uint64buf)
+		m.Entries = make([]raftpb.Entry, int(l))
+		for i := 0; i < int(l); i++ {
+			if _, err := io.ReadFull(dec.r, dec.uint64buf); err != nil {
+				return m, err
+			}
+			size := binary.BigEndian.Uint64(dec.uint64buf)
+			var buf []byte
+			if size < msgAppV2BufSize {
+				buf = dec.buf[:size]
+				if _, err := io.ReadFull(dec.r, buf); err != nil {
+					return m, err
+				}
+			} else {
+				buf = make([]byte, int(size))
+				if _, err := io.ReadFull(dec.r, buf); err != nil {
+					return m, err
+				}
+			}
+			dec.index++
+			// 1 alloc
+			pbutil.MustUnmarshal(&m.Entries[i], buf)
+		}
+		// decode commit index
+		if _, err := io.ReadFull(dec.r, dec.uint64buf); err != nil {
+			return m, err
+		}
+		m.Commit = binary.BigEndian.Uint64(dec.uint64buf)
+	case msgTypeApp:
+		var size uint64
+		if err := binary.Read(dec.r, binary.BigEndian, &size); err != nil {
+			return m, err
+		}
+		buf := make([]byte, int(size))
+		if _, err := io.ReadFull(dec.r, buf); err != nil {
+			return m, err
+		}
+		pbutil.MustUnmarshal(&m, buf)
+
+		dec.term = m.Term
+		dec.index = m.Index
+		if l := len(m.Entries); l > 0 {
+			dec.index = m.Entries[l-1].Index
+		}
+	default:
+		return m, fmt.Errorf("failed to parse type %d in msgappv2 stream", typ)
+	}
+	return m, nil
+}