mu        sync.Mutex
	init      sync.Once
	lastMinuteLatency
}

func (e *lockedLastMinuteLatency) add(value time.Duration) {
	e.addSize(value, 0)
}

// addSize will add a duration and size.
func (e *lockedLastMinuteLatency) addSize(value time.Duration, sz int64) {
	// alloc on every call, so we have a clean entry to swap in.
	t := time.Now().Unix()
	e.init.Do(func() {
		e.cached.Store(&AccElem{})