diff --git a/vendor/github.com/coreos/etcd/etcdserver/stats/leader.go b/vendor/github.com/coreos/etcd/etcdserver/stats/leader.go
new file mode 100644
index 0000000..8f6a54f
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/etcdserver/stats/leader.go
@@ -0,0 +1,128 @@
+// 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 stats
+
+import (
+	"encoding/json"
+	"math"
+	"sync"
+	"time"
+)
+
+// LeaderStats is used by the leader in an etcd cluster, and encapsulates
+// statistics about communication with its followers
+type LeaderStats struct {
+	leaderStats
+	sync.Mutex
+}
+
+type leaderStats struct {
+	// Leader is the ID of the leader in the etcd cluster.
+	// TODO(jonboulle): clarify that these are IDs, not names
+	Leader    string                    `json:"leader"`
+	Followers map[string]*FollowerStats `json:"followers"`
+}
+
+// NewLeaderStats generates a new LeaderStats with the given id as leader
+func NewLeaderStats(id string) *LeaderStats {
+	return &LeaderStats{
+		leaderStats: leaderStats{
+			Leader:    id,
+			Followers: make(map[string]*FollowerStats),
+		},
+	}
+}
+
+func (ls *LeaderStats) JSON() []byte {
+	ls.Lock()
+	stats := ls.leaderStats
+	ls.Unlock()
+	b, err := json.Marshal(stats)
+	// TODO(jonboulle): appropriate error handling?
+	if err != nil {
+		plog.Errorf("error marshalling leader stats (%v)", err)
+	}
+	return b
+}
+
+func (ls *LeaderStats) Follower(name string) *FollowerStats {
+	ls.Lock()
+	defer ls.Unlock()
+	fs, ok := ls.Followers[name]
+	if !ok {
+		fs = &FollowerStats{}
+		fs.Latency.Minimum = 1 << 63
+		ls.Followers[name] = fs
+	}
+	return fs
+}
+
+// FollowerStats encapsulates various statistics about a follower in an etcd cluster
+type FollowerStats struct {
+	Latency LatencyStats `json:"latency"`
+	Counts  CountsStats  `json:"counts"`
+
+	sync.Mutex
+}
+
+// LatencyStats encapsulates latency statistics.
+type LatencyStats struct {
+	Current           float64 `json:"current"`
+	Average           float64 `json:"average"`
+	averageSquare     float64
+	StandardDeviation float64 `json:"standardDeviation"`
+	Minimum           float64 `json:"minimum"`
+	Maximum           float64 `json:"maximum"`
+}
+
+// CountsStats encapsulates raft statistics.
+type CountsStats struct {
+	Fail    uint64 `json:"fail"`
+	Success uint64 `json:"success"`
+}
+
+// Succ updates the FollowerStats with a successful send
+func (fs *FollowerStats) Succ(d time.Duration) {
+	fs.Lock()
+	defer fs.Unlock()
+
+	total := float64(fs.Counts.Success) * fs.Latency.Average
+	totalSquare := float64(fs.Counts.Success) * fs.Latency.averageSquare
+
+	fs.Counts.Success++
+
+	fs.Latency.Current = float64(d) / (1000000.0)
+
+	if fs.Latency.Current > fs.Latency.Maximum {
+		fs.Latency.Maximum = fs.Latency.Current
+	}
+
+	if fs.Latency.Current < fs.Latency.Minimum {
+		fs.Latency.Minimum = fs.Latency.Current
+	}
+
+	fs.Latency.Average = (total + fs.Latency.Current) / float64(fs.Counts.Success)
+	fs.Latency.averageSquare = (totalSquare + fs.Latency.Current*fs.Latency.Current) / float64(fs.Counts.Success)
+
+	// sdv = sqrt(avg(x^2) - avg(x)^2)
+	fs.Latency.StandardDeviation = math.Sqrt(fs.Latency.averageSquare - fs.Latency.Average*fs.Latency.Average)
+}
+
+// Fail updates the FollowerStats with an unsuccessful send
+func (fs *FollowerStats) Fail() {
+	fs.Lock()
+	defer fs.Unlock()
+	fs.Counts.Fail++
+}