package main import ( "sync/atomic" "time" ) type Event struct { guard int32 next time.Time interval time.Duration C chan struct{} } func newEvent(interval time.Duration) *Event { return &Event{ guard: 0, next: time.Now(), interval: interval, C: make(chan struct{}, 1), } } func (e *Event) Clear() { select { case <-e.C: default: } } func (e *Event) Fire() { if e == nil || atomic.SwapInt32(&e.guard, 1) != 0 { return } now := time.Now() if e.next.After(now) { select { case e.C <- struct{}{}: default: } e.next = now.Add(e.interval) } atomic.StoreInt32(&e.guard, 0) }