timer

type Provider interface {
	// NewTimer creates a new Timer that is to expire at least
	// after duration d.
	NewTimer(d time.Duration) Timer

	// AfterFunc creates a new Timer that is to expire at least
	// after duration d. The supplied callback function f is
	// invoked in a spawned goroutine upon the timer expiration.
	AfterFunc(d time.Duration, f func()) Timer
}

type Timer interface {
	// Expired returns a channel to receive the current time when
	// the timer expires.
	Expired() <-chan time.Time

	// Reset reschedules the timer to expire after duration d. It
	// should only be used on an inactive timer.
	Reset(d time.Duration)

	// Stop cancels the timer. It returns true if the timer has
	// been stopped by this invocation before expiration.
	Stop() bool
}