diff --git a/vendor/go.etcd.io/etcd/etcdserver/api/rafthttp/transport.go b/vendor/go.etcd.io/etcd/etcdserver/api/rafthttp/transport.go
new file mode 100644
index 0000000..7191c3d
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/etcdserver/api/rafthttp/transport.go
@@ -0,0 +1,467 @@
+// 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 (
+	"context"
+	"net/http"
+	"sync"
+	"time"
+
+	"go.etcd.io/etcd/etcdserver/api/snap"
+	stats "go.etcd.io/etcd/etcdserver/api/v2stats"
+	"go.etcd.io/etcd/pkg/logutil"
+	"go.etcd.io/etcd/pkg/transport"
+	"go.etcd.io/etcd/pkg/types"
+	"go.etcd.io/etcd/raft"
+	"go.etcd.io/etcd/raft/raftpb"
+
+	"github.com/coreos/pkg/capnslog"
+	"github.com/xiang90/probing"
+	"go.uber.org/zap"
+	"golang.org/x/time/rate"
+)
+
+var plog = logutil.NewMergeLogger(capnslog.NewPackageLogger("go.etcd.io/etcd", "rafthttp"))
+
+type Raft interface {
+	Process(ctx context.Context, m raftpb.Message) error
+	IsIDRemoved(id uint64) bool
+	ReportUnreachable(id uint64)
+	ReportSnapshot(id uint64, status raft.SnapshotStatus)
+}
+
+type Transporter interface {
+	// Start starts the given Transporter.
+	// Start MUST be called before calling other functions in the interface.
+	Start() error
+	// Handler returns the HTTP handler of the transporter.
+	// A transporter HTTP handler handles the HTTP requests
+	// from remote peers.
+	// The handler MUST be used to handle RaftPrefix(/raft)
+	// endpoint.
+	Handler() http.Handler
+	// Send sends out the given messages to the remote peers.
+	// Each message has a To field, which is an id that maps
+	// to an existing peer in the transport.
+	// If the id cannot be found in the transport, the message
+	// will be ignored.
+	Send(m []raftpb.Message)
+	// SendSnapshot sends out the given snapshot message to a remote peer.
+	// The behavior of SendSnapshot is similar to Send.
+	SendSnapshot(m snap.Message)
+	// AddRemote adds a remote with given peer urls into the transport.
+	// A remote helps newly joined member to catch up the progress of cluster,
+	// and will not be used after that.
+	// It is the caller's responsibility to ensure the urls are all valid,
+	// or it panics.
+	AddRemote(id types.ID, urls []string)
+	// AddPeer adds a peer with given peer urls into the transport.
+	// It is the caller's responsibility to ensure the urls are all valid,
+	// or it panics.
+	// Peer urls are used to connect to the remote peer.
+	AddPeer(id types.ID, urls []string)
+	// RemovePeer removes the peer with given id.
+	RemovePeer(id types.ID)
+	// RemoveAllPeers removes all the existing peers in the transport.
+	RemoveAllPeers()
+	// UpdatePeer updates the peer urls of the peer with the given id.
+	// It is the caller's responsibility to ensure the urls are all valid,
+	// or it panics.
+	UpdatePeer(id types.ID, urls []string)
+	// ActiveSince returns the time that the connection with the peer
+	// of the given id becomes active.
+	// If the connection is active since peer was added, it returns the adding time.
+	// If the connection is currently inactive, it returns zero time.
+	ActiveSince(id types.ID) time.Time
+	// ActivePeers returns the number of active peers.
+	ActivePeers() int
+	// Stop closes the connections and stops the transporter.
+	Stop()
+}
+
+// Transport implements Transporter interface. It provides the functionality
+// to send raft messages to peers, and receive raft messages from peers.
+// User should call Handler method to get a handler to serve requests
+// received from peerURLs.
+// User needs to call Start before calling other functions, and call
+// Stop when the Transport is no longer used.
+type Transport struct {
+	Logger *zap.Logger
+
+	DialTimeout time.Duration // maximum duration before timing out dial of the request
+	// DialRetryFrequency defines the frequency of streamReader dial retrial attempts;
+	// a distinct rate limiter is created per every peer (default value: 10 events/sec)
+	DialRetryFrequency rate.Limit
+
+	TLSInfo transport.TLSInfo // TLS information used when creating connection
+
+	ID          types.ID   // local member ID
+	URLs        types.URLs // local peer URLs
+	ClusterID   types.ID   // raft cluster ID for request validation
+	Raft        Raft       // raft state machine, to which the Transport forwards received messages and reports status
+	Snapshotter *snap.Snapshotter
+	ServerStats *stats.ServerStats // used to record general transportation statistics
+	// used to record transportation statistics with followers when
+	// performing as leader in raft protocol
+	LeaderStats *stats.LeaderStats
+	// ErrorC is used to report detected critical errors, e.g.,
+	// the member has been permanently removed from the cluster
+	// When an error is received from ErrorC, user should stop raft state
+	// machine and thus stop the Transport.
+	ErrorC chan error
+
+	streamRt   http.RoundTripper // roundTripper used by streams
+	pipelineRt http.RoundTripper // roundTripper used by pipelines
+
+	mu      sync.RWMutex         // protect the remote and peer map
+	remotes map[types.ID]*remote // remotes map that helps newly joined member to catch up
+	peers   map[types.ID]Peer    // peers map
+
+	pipelineProber probing.Prober
+	streamProber   probing.Prober
+}
+
+func (t *Transport) Start() error {
+	var err error
+	t.streamRt, err = newStreamRoundTripper(t.TLSInfo, t.DialTimeout)
+	if err != nil {
+		return err
+	}
+	t.pipelineRt, err = NewRoundTripper(t.TLSInfo, t.DialTimeout)
+	if err != nil {
+		return err
+	}
+	t.remotes = make(map[types.ID]*remote)
+	t.peers = make(map[types.ID]Peer)
+	t.pipelineProber = probing.NewProber(t.pipelineRt)
+	t.streamProber = probing.NewProber(t.streamRt)
+
+	// If client didn't provide dial retry frequency, use the default
+	// (100ms backoff between attempts to create a new stream),
+	// so it doesn't bring too much overhead when retry.
+	if t.DialRetryFrequency == 0 {
+		t.DialRetryFrequency = rate.Every(100 * time.Millisecond)
+	}
+	return nil
+}
+
+func (t *Transport) Handler() http.Handler {
+	pipelineHandler := newPipelineHandler(t, t.Raft, t.ClusterID)
+	streamHandler := newStreamHandler(t, t, t.Raft, t.ID, t.ClusterID)
+	snapHandler := newSnapshotHandler(t, t.Raft, t.Snapshotter, t.ClusterID)
+	mux := http.NewServeMux()
+	mux.Handle(RaftPrefix, pipelineHandler)
+	mux.Handle(RaftStreamPrefix+"/", streamHandler)
+	mux.Handle(RaftSnapshotPrefix, snapHandler)
+	mux.Handle(ProbingPrefix, probing.NewHandler())
+	return mux
+}
+
+func (t *Transport) Get(id types.ID) Peer {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	return t.peers[id]
+}
+
+func (t *Transport) Send(msgs []raftpb.Message) {
+	for _, m := range msgs {
+		if m.To == 0 {
+			// ignore intentionally dropped message
+			continue
+		}
+		to := types.ID(m.To)
+
+		t.mu.RLock()
+		p, pok := t.peers[to]
+		g, rok := t.remotes[to]
+		t.mu.RUnlock()
+
+		if pok {
+			if m.Type == raftpb.MsgApp {
+				t.ServerStats.SendAppendReq(m.Size())
+			}
+			p.send(m)
+			continue
+		}
+
+		if rok {
+			g.send(m)
+			continue
+		}
+
+		if t.Logger != nil {
+			t.Logger.Debug(
+				"ignored message send request; unknown remote peer target",
+				zap.String("type", m.Type.String()),
+				zap.String("unknown-target-peer-id", to.String()),
+			)
+		} else {
+			plog.Debugf("ignored message %s (sent to unknown peer %s)", m.Type, to)
+		}
+	}
+}
+
+func (t *Transport) Stop() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	for _, r := range t.remotes {
+		r.stop()
+	}
+	for _, p := range t.peers {
+		p.stop()
+	}
+	t.pipelineProber.RemoveAll()
+	t.streamProber.RemoveAll()
+	if tr, ok := t.streamRt.(*http.Transport); ok {
+		tr.CloseIdleConnections()
+	}
+	if tr, ok := t.pipelineRt.(*http.Transport); ok {
+		tr.CloseIdleConnections()
+	}
+	t.peers = nil
+	t.remotes = nil
+}
+
+// CutPeer drops messages to the specified peer.
+func (t *Transport) CutPeer(id types.ID) {
+	t.mu.RLock()
+	p, pok := t.peers[id]
+	g, gok := t.remotes[id]
+	t.mu.RUnlock()
+
+	if pok {
+		p.(Pausable).Pause()
+	}
+	if gok {
+		g.Pause()
+	}
+}
+
+// MendPeer recovers the message dropping behavior of the given peer.
+func (t *Transport) MendPeer(id types.ID) {
+	t.mu.RLock()
+	p, pok := t.peers[id]
+	g, gok := t.remotes[id]
+	t.mu.RUnlock()
+
+	if pok {
+		p.(Pausable).Resume()
+	}
+	if gok {
+		g.Resume()
+	}
+}
+
+func (t *Transport) AddRemote(id types.ID, us []string) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	if t.remotes == nil {
+		// there's no clean way to shutdown the golang http server
+		// (see: https://github.com/golang/go/issues/4674) before
+		// stopping the transport; ignore any new connections.
+		return
+	}
+	if _, ok := t.peers[id]; ok {
+		return
+	}
+	if _, ok := t.remotes[id]; ok {
+		return
+	}
+	urls, err := types.NewURLs(us)
+	if err != nil {
+		if t.Logger != nil {
+			t.Logger.Panic("failed NewURLs", zap.Strings("urls", us), zap.Error(err))
+		} else {
+			plog.Panicf("newURLs %+v should never fail: %+v", us, err)
+		}
+	}
+	t.remotes[id] = startRemote(t, urls, id)
+
+	if t.Logger != nil {
+		t.Logger.Info(
+			"added new remote peer",
+			zap.String("local-member-id", t.ID.String()),
+			zap.String("remote-peer-id", id.String()),
+			zap.Strings("remote-peer-urls", us),
+		)
+	}
+}
+
+func (t *Transport) AddPeer(id types.ID, us []string) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	if t.peers == nil {
+		panic("transport stopped")
+	}
+	if _, ok := t.peers[id]; ok {
+		return
+	}
+	urls, err := types.NewURLs(us)
+	if err != nil {
+		if t.Logger != nil {
+			t.Logger.Panic("failed NewURLs", zap.Strings("urls", us), zap.Error(err))
+		} else {
+			plog.Panicf("newURLs %+v should never fail: %+v", us, err)
+		}
+	}
+	fs := t.LeaderStats.Follower(id.String())
+	t.peers[id] = startPeer(t, urls, id, fs)
+	addPeerToProber(t.Logger, t.pipelineProber, id.String(), us, RoundTripperNameSnapshot, rttSec)
+	addPeerToProber(t.Logger, t.streamProber, id.String(), us, RoundTripperNameRaftMessage, rttSec)
+
+	if t.Logger != nil {
+		t.Logger.Info(
+			"added remote peer",
+			zap.String("local-member-id", t.ID.String()),
+			zap.String("remote-peer-id", id.String()),
+			zap.Strings("remote-peer-urls", us),
+		)
+	} else {
+		plog.Infof("added peer %s", id)
+	}
+}
+
+func (t *Transport) RemovePeer(id types.ID) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	t.removePeer(id)
+}
+
+func (t *Transport) RemoveAllPeers() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	for id := range t.peers {
+		t.removePeer(id)
+	}
+}
+
+// the caller of this function must have the peers mutex.
+func (t *Transport) removePeer(id types.ID) {
+	if peer, ok := t.peers[id]; ok {
+		peer.stop()
+	} else {
+		if t.Logger != nil {
+			t.Logger.Panic("unexpected removal of unknown remote peer", zap.String("remote-peer-id", id.String()))
+		} else {
+			plog.Panicf("unexpected removal of unknown peer '%d'", id)
+		}
+	}
+	delete(t.peers, id)
+	delete(t.LeaderStats.Followers, id.String())
+	t.pipelineProber.Remove(id.String())
+	t.streamProber.Remove(id.String())
+
+	if t.Logger != nil {
+		t.Logger.Info(
+			"removed remote peer",
+			zap.String("local-member-id", t.ID.String()),
+			zap.String("removed-remote-peer-id", id.String()),
+		)
+	} else {
+		plog.Infof("removed peer %s", id)
+	}
+}
+
+func (t *Transport) UpdatePeer(id types.ID, us []string) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	// TODO: return error or just panic?
+	if _, ok := t.peers[id]; !ok {
+		return
+	}
+	urls, err := types.NewURLs(us)
+	if err != nil {
+		if t.Logger != nil {
+			t.Logger.Panic("failed NewURLs", zap.Strings("urls", us), zap.Error(err))
+		} else {
+			plog.Panicf("newURLs %+v should never fail: %+v", us, err)
+		}
+	}
+	t.peers[id].update(urls)
+
+	t.pipelineProber.Remove(id.String())
+	addPeerToProber(t.Logger, t.pipelineProber, id.String(), us, RoundTripperNameSnapshot, rttSec)
+	t.streamProber.Remove(id.String())
+	addPeerToProber(t.Logger, t.streamProber, id.String(), us, RoundTripperNameRaftMessage, rttSec)
+
+	if t.Logger != nil {
+		t.Logger.Info(
+			"updated remote peer",
+			zap.String("local-member-id", t.ID.String()),
+			zap.String("updated-remote-peer-id", id.String()),
+			zap.Strings("updated-remote-peer-urls", us),
+		)
+	} else {
+		plog.Infof("updated peer %s", id)
+	}
+}
+
+func (t *Transport) ActiveSince(id types.ID) time.Time {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	if p, ok := t.peers[id]; ok {
+		return p.activeSince()
+	}
+	return time.Time{}
+}
+
+func (t *Transport) SendSnapshot(m snap.Message) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	p := t.peers[types.ID(m.To)]
+	if p == nil {
+		m.CloseWithError(errMemberNotFound)
+		return
+	}
+	p.sendSnap(m)
+}
+
+// Pausable is a testing interface for pausing transport traffic.
+type Pausable interface {
+	Pause()
+	Resume()
+}
+
+func (t *Transport) Pause() {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	for _, p := range t.peers {
+		p.(Pausable).Pause()
+	}
+}
+
+func (t *Transport) Resume() {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	for _, p := range t.peers {
+		p.(Pausable).Resume()
+	}
+}
+
+// ActivePeers returns a channel that closes when an initial
+// peer connection has been established. Use this to wait until the
+// first peer connection becomes active.
+func (t *Transport) ActivePeers() (cnt int) {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	for _, p := range t.peers {
+		if !p.activeSince().IsZero() {
+			cnt++
+		}
+	}
+	return cnt
+}