Add Meter::Reset method

meter.go

@@ -53,6 +53,16 @@ func (m *Meter) Snapshot() Snapshot {
 	return m.snapshot
 }
 
+// Reset sets accumulator, total and rate to zero and last update to current time.
+func (m *Meter) Reset() {
+	globalSweeper.snapshotMu.Lock()
+	defer globalSweeper.snapshotMu.Unlock()
+	atomic.StoreUint64(&m.accumulator, 0)
+	m.snapshot.Rate = 0
+	m.snapshot.Total = 0
+	m.snapshot.LastUpdate = time.Now()
+}
+
 func (m *Meter) String() string {
 	return m.Snapshot().String()
 }