diff --git a/vendor/github.com/coreos/etcd/pkg/idutil/id.go b/vendor/github.com/coreos/etcd/pkg/idutil/id.go
new file mode 100644
index 0000000..2da2106
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/pkg/idutil/id.go
@@ -0,0 +1,78 @@
+// 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 idutil implements utility functions for generating unique,
+// randomized ids.
+package idutil
+
+import (
+	"math"
+	"sync"
+	"time"
+)
+
+const (
+	tsLen     = 5 * 8
+	cntLen    = 8
+	suffixLen = tsLen + cntLen
+)
+
+// Generator generates unique identifiers based on counters, timestamps, and
+// a node member ID.
+//
+// The initial id is in this format:
+// High order 2 bytes are from memberID, next 5 bytes are from timestamp,
+// and low order one byte is a counter.
+// | prefix   | suffix              |
+// | 2 bytes  | 5 bytes   | 1 byte  |
+// | memberID | timestamp | cnt     |
+//
+// The timestamp 5 bytes is different when the machine is restart
+// after 1 ms and before 35 years.
+//
+// It increases suffix to generate the next id.
+// The count field may overflow to timestamp field, which is intentional.
+// It helps to extend the event window to 2^56. This doesn't break that
+// id generated after restart is unique because etcd throughput is <<
+// 256req/ms(250k reqs/second).
+type Generator struct {
+	mu sync.Mutex
+	// high order 2 bytes
+	prefix uint64
+	// low order 6 bytes
+	suffix uint64
+}
+
+func NewGenerator(memberID uint16, now time.Time) *Generator {
+	prefix := uint64(memberID) << suffixLen
+	unixMilli := uint64(now.UnixNano()) / uint64(time.Millisecond/time.Nanosecond)
+	suffix := lowbit(unixMilli, tsLen) << cntLen
+	return &Generator{
+		prefix: prefix,
+		suffix: suffix,
+	}
+}
+
+// Next generates a id that is unique.
+func (g *Generator) Next() uint64 {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+	g.suffix++
+	id := g.prefix | lowbit(g.suffix, suffixLen)
+	return id
+}
+
+func lowbit(x uint64, n uint) uint64 {
+	return x & (math.MaxUint64 >> (64 - n))
+}