diff --git a/vendor/go.etcd.io/etcd/etcdserver/util.go b/vendor/go.etcd.io/etcd/etcdserver/util.go
new file mode 100644
index 0000000..fe5024e
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/etcdserver/util.go
@@ -0,0 +1,168 @@
+// 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 etcdserver
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+	"go.etcd.io/etcd/etcdserver/api/membership"
+	"go.etcd.io/etcd/etcdserver/api/rafthttp"
+	pb "go.etcd.io/etcd/etcdserver/etcdserverpb"
+	"go.etcd.io/etcd/pkg/types"
+
+	"go.uber.org/zap"
+)
+
+// isConnectedToQuorumSince checks whether the local member is connected to the
+// quorum of the cluster since the given time.
+func isConnectedToQuorumSince(transport rafthttp.Transporter, since time.Time, self types.ID, members []*membership.Member) bool {
+	return numConnectedSince(transport, since, self, members) >= (len(members)/2)+1
+}
+
+// isConnectedSince checks whether the local member is connected to the
+// remote member since the given time.
+func isConnectedSince(transport rafthttp.Transporter, since time.Time, remote types.ID) bool {
+	t := transport.ActiveSince(remote)
+	return !t.IsZero() && t.Before(since)
+}
+
+// isConnectedFullySince checks whether the local member is connected to all
+// members in the cluster since the given time.
+func isConnectedFullySince(transport rafthttp.Transporter, since time.Time, self types.ID, members []*membership.Member) bool {
+	return numConnectedSince(transport, since, self, members) == len(members)
+}
+
+// numConnectedSince counts how many members are connected to the local member
+// since the given time.
+func numConnectedSince(transport rafthttp.Transporter, since time.Time, self types.ID, members []*membership.Member) int {
+	connectedNum := 0
+	for _, m := range members {
+		if m.ID == self || isConnectedSince(transport, since, m.ID) {
+			connectedNum++
+		}
+	}
+	return connectedNum
+}
+
+// longestConnected chooses the member with longest active-since-time.
+// It returns false, if nothing is active.
+func longestConnected(tp rafthttp.Transporter, membs []types.ID) (types.ID, bool) {
+	var longest types.ID
+	var oldest time.Time
+	for _, id := range membs {
+		tm := tp.ActiveSince(id)
+		if tm.IsZero() { // inactive
+			continue
+		}
+
+		if oldest.IsZero() { // first longest candidate
+			oldest = tm
+			longest = id
+		}
+
+		if tm.Before(oldest) {
+			oldest = tm
+			longest = id
+		}
+	}
+	if uint64(longest) == 0 {
+		return longest, false
+	}
+	return longest, true
+}
+
+type notifier struct {
+	c   chan struct{}
+	err error
+}
+
+func newNotifier() *notifier {
+	return &notifier{
+		c: make(chan struct{}),
+	}
+}
+
+func (nc *notifier) notify(err error) {
+	nc.err = err
+	close(nc.c)
+}
+
+func warnOfExpensiveRequest(lg *zap.Logger, now time.Time, reqStringer fmt.Stringer, respMsg proto.Message, err error) {
+	var resp string
+	if !isNil(respMsg) {
+		resp = fmt.Sprintf("size:%d", proto.Size(respMsg))
+	}
+	warnOfExpensiveGenericRequest(lg, now, reqStringer, "", resp, err)
+}
+
+func warnOfExpensiveReadOnlyTxnRequest(lg *zap.Logger, now time.Time, r *pb.TxnRequest, txnResponse *pb.TxnResponse, err error) {
+	reqStringer := pb.NewLoggableTxnRequest(r)
+	var resp string
+	if !isNil(txnResponse) {
+		var resps []string
+		for _, r := range txnResponse.Responses {
+			switch op := r.Response.(type) {
+			case *pb.ResponseOp_ResponseRange:
+				resps = append(resps, fmt.Sprintf("range_response_count:%d", len(op.ResponseRange.Kvs)))
+			default:
+				// only range responses should be in a read only txn request
+			}
+		}
+		resp = fmt.Sprintf("responses:<%s> size:%d", strings.Join(resps, " "), proto.Size(txnResponse))
+	}
+	warnOfExpensiveGenericRequest(lg, now, reqStringer, "read-only range ", resp, err)
+}
+
+func warnOfExpensiveReadOnlyRangeRequest(lg *zap.Logger, now time.Time, reqStringer fmt.Stringer, rangeResponse *pb.RangeResponse, err error) {
+	var resp string
+	if !isNil(rangeResponse) {
+		resp = fmt.Sprintf("range_response_count:%d size:%d", len(rangeResponse.Kvs), proto.Size(rangeResponse))
+	}
+	warnOfExpensiveGenericRequest(lg, now, reqStringer, "read-only range ", resp, err)
+}
+
+func warnOfExpensiveGenericRequest(lg *zap.Logger, now time.Time, reqStringer fmt.Stringer, prefix string, resp string, err error) {
+	d := time.Since(now)
+	if d > warnApplyDuration {
+		if lg != nil {
+			lg.Warn(
+				"apply request took too long",
+				zap.Duration("took", d),
+				zap.Duration("expected-duration", warnApplyDuration),
+				zap.String("prefix", prefix),
+				zap.String("request", reqStringer.String()),
+				zap.String("response", resp),
+				zap.Error(err),
+			)
+		} else {
+			var result string
+			if err != nil {
+				result = fmt.Sprintf("error:%v", err)
+			} else {
+				result = resp
+			}
+			plog.Warningf("%srequest %q with result %q took too long (%v) to execute", prefix, reqStringer.String(), result, d)
+		}
+		slowApplies.Inc()
+	}
+}
+
+func isNil(msg proto.Message) bool {
+	return msg == nil || reflect.ValueOf(msg).IsNil()
+}