diff --git a/vendor/github.com/rcrowley/go-metrics/meter.go b/vendor/github.com/rcrowley/go-metrics/meter.go
new file mode 100644
index 0000000..223669b
--- /dev/null
+++ b/vendor/github.com/rcrowley/go-metrics/meter.go
@@ -0,0 +1,251 @@
+package metrics
+
+import (
+	"math"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// Meters count events to produce exponentially-weighted moving average rates
+// at one-, five-, and fifteen-minutes and a mean rate.
+type Meter interface {
+	Count() int64
+	Mark(int64)
+	Rate1() float64
+	Rate5() float64
+	Rate15() float64
+	RateMean() float64
+	Snapshot() Meter
+	Stop()
+}
+
+// GetOrRegisterMeter returns an existing Meter or constructs and registers a
+// new StandardMeter.
+// Be sure to unregister the meter from the registry once it is of no use to
+// allow for garbage collection.
+func GetOrRegisterMeter(name string, r Registry) Meter {
+	if nil == r {
+		r = DefaultRegistry
+	}
+	return r.GetOrRegister(name, NewMeter).(Meter)
+}
+
+// NewMeter constructs a new StandardMeter and launches a goroutine.
+// Be sure to call Stop() once the meter is of no use to allow for garbage collection.
+func NewMeter() Meter {
+	if UseNilMetrics {
+		return NilMeter{}
+	}
+	m := newStandardMeter()
+	arbiter.Lock()
+	defer arbiter.Unlock()
+	arbiter.meters[m] = struct{}{}
+	if !arbiter.started {
+		arbiter.started = true
+		go arbiter.tick()
+	}
+	return m
+}
+
+// NewMeter constructs and registers a new StandardMeter and launches a
+// goroutine.
+// Be sure to unregister the meter from the registry once it is of no use to
+// allow for garbage collection.
+func NewRegisteredMeter(name string, r Registry) Meter {
+	c := NewMeter()
+	if nil == r {
+		r = DefaultRegistry
+	}
+	r.Register(name, c)
+	return c
+}
+
+// MeterSnapshot is a read-only copy of another Meter.
+type MeterSnapshot struct {
+	count                          int64
+	rate1, rate5, rate15, rateMean uint64
+}
+
+// Count returns the count of events at the time the snapshot was taken.
+func (m *MeterSnapshot) Count() int64 { return m.count }
+
+// Mark panics.
+func (*MeterSnapshot) Mark(n int64) {
+	panic("Mark called on a MeterSnapshot")
+}
+
+// Rate1 returns the one-minute moving average rate of events per second at the
+// time the snapshot was taken.
+func (m *MeterSnapshot) Rate1() float64 { return math.Float64frombits(m.rate1) }
+
+// Rate5 returns the five-minute moving average rate of events per second at
+// the time the snapshot was taken.
+func (m *MeterSnapshot) Rate5() float64 { return math.Float64frombits(m.rate5) }
+
+// Rate15 returns the fifteen-minute moving average rate of events per second
+// at the time the snapshot was taken.
+func (m *MeterSnapshot) Rate15() float64 { return math.Float64frombits(m.rate15) }
+
+// RateMean returns the meter's mean rate of events per second at the time the
+// snapshot was taken.
+func (m *MeterSnapshot) RateMean() float64 { return math.Float64frombits(m.rateMean) }
+
+// Snapshot returns the snapshot.
+func (m *MeterSnapshot) Snapshot() Meter { return m }
+
+// Stop is a no-op.
+func (m *MeterSnapshot) Stop() {}
+
+// NilMeter is a no-op Meter.
+type NilMeter struct{}
+
+// Count is a no-op.
+func (NilMeter) Count() int64 { return 0 }
+
+// Mark is a no-op.
+func (NilMeter) Mark(n int64) {}
+
+// Rate1 is a no-op.
+func (NilMeter) Rate1() float64 { return 0.0 }
+
+// Rate5 is a no-op.
+func (NilMeter) Rate5() float64 { return 0.0 }
+
+// Rate15is a no-op.
+func (NilMeter) Rate15() float64 { return 0.0 }
+
+// RateMean is a no-op.
+func (NilMeter) RateMean() float64 { return 0.0 }
+
+// Snapshot is a no-op.
+func (NilMeter) Snapshot() Meter { return NilMeter{} }
+
+// Stop is a no-op.
+func (NilMeter) Stop() {}
+
+// StandardMeter is the standard implementation of a Meter.
+type StandardMeter struct {
+	snapshot    *MeterSnapshot
+	a1, a5, a15 EWMA
+	startTime   time.Time
+	stopped     uint32
+}
+
+func newStandardMeter() *StandardMeter {
+	return &StandardMeter{
+		snapshot:  &MeterSnapshot{},
+		a1:        NewEWMA1(),
+		a5:        NewEWMA5(),
+		a15:       NewEWMA15(),
+		startTime: time.Now(),
+	}
+}
+
+// Stop stops the meter, Mark() will be a no-op if you use it after being stopped.
+func (m *StandardMeter) Stop() {
+	if atomic.CompareAndSwapUint32(&m.stopped, 0, 1) {
+		arbiter.Lock()
+		delete(arbiter.meters, m)
+		arbiter.Unlock()
+	}
+}
+
+// Count returns the number of events recorded.
+func (m *StandardMeter) Count() int64 {
+	return atomic.LoadInt64(&m.snapshot.count)
+}
+
+// Mark records the occurance of n events.
+func (m *StandardMeter) Mark(n int64) {
+	if atomic.LoadUint32(&m.stopped) == 1 {
+		return
+	}
+
+	atomic.AddInt64(&m.snapshot.count, n)
+
+	m.a1.Update(n)
+	m.a5.Update(n)
+	m.a15.Update(n)
+	m.updateSnapshot()
+}
+
+// Rate1 returns the one-minute moving average rate of events per second.
+func (m *StandardMeter) Rate1() float64 {
+	return math.Float64frombits(atomic.LoadUint64(&m.snapshot.rate1))
+}
+
+// Rate5 returns the five-minute moving average rate of events per second.
+func (m *StandardMeter) Rate5() float64 {
+	return math.Float64frombits(atomic.LoadUint64(&m.snapshot.rate5))
+}
+
+// Rate15 returns the fifteen-minute moving average rate of events per second.
+func (m *StandardMeter) Rate15() float64 {
+	return math.Float64frombits(atomic.LoadUint64(&m.snapshot.rate15))
+}
+
+// RateMean returns the meter's mean rate of events per second.
+func (m *StandardMeter) RateMean() float64 {
+	return math.Float64frombits(atomic.LoadUint64(&m.snapshot.rateMean))
+}
+
+// Snapshot returns a read-only copy of the meter.
+func (m *StandardMeter) Snapshot() Meter {
+	copiedSnapshot := MeterSnapshot{
+		count:    atomic.LoadInt64(&m.snapshot.count),
+		rate1:    atomic.LoadUint64(&m.snapshot.rate1),
+		rate5:    atomic.LoadUint64(&m.snapshot.rate5),
+		rate15:   atomic.LoadUint64(&m.snapshot.rate15),
+		rateMean: atomic.LoadUint64(&m.snapshot.rateMean),
+	}
+	return &copiedSnapshot
+}
+
+func (m *StandardMeter) updateSnapshot() {
+	rate1 := math.Float64bits(m.a1.Rate())
+	rate5 := math.Float64bits(m.a5.Rate())
+	rate15 := math.Float64bits(m.a15.Rate())
+	rateMean := math.Float64bits(float64(m.Count()) / time.Since(m.startTime).Seconds())
+
+	atomic.StoreUint64(&m.snapshot.rate1, rate1)
+	atomic.StoreUint64(&m.snapshot.rate5, rate5)
+	atomic.StoreUint64(&m.snapshot.rate15, rate15)
+	atomic.StoreUint64(&m.snapshot.rateMean, rateMean)
+}
+
+func (m *StandardMeter) tick() {
+	m.a1.Tick()
+	m.a5.Tick()
+	m.a15.Tick()
+	m.updateSnapshot()
+}
+
+// meterArbiter ticks meters every 5s from a single goroutine.
+// meters are references in a set for future stopping.
+type meterArbiter struct {
+	sync.RWMutex
+	started bool
+	meters  map[*StandardMeter]struct{}
+	ticker  *time.Ticker
+}
+
+var arbiter = meterArbiter{ticker: time.NewTicker(5e9), meters: make(map[*StandardMeter]struct{})}
+
+// Ticks meters on the scheduled interval
+func (ma *meterArbiter) tick() {
+	for {
+		select {
+		case <-ma.ticker.C:
+			ma.tickMeters()
+		}
+	}
+}
+
+func (ma *meterArbiter) tickMeters() {
+	ma.RLock()
+	defer ma.RUnlock()
+	for meter := range ma.meters {
+		meter.tick()
+	}
+}