clock

type Clock interface {
	// Returns the current time (see time.Now).
	Now() time.Time

	// Sleeps the current goroutine (see time.Sleep).
	//
	// Sleep will return a TimerResult containing the time when it was awakened
	// and detailing its execution. If the sleep terminated prematurely from
	// cancellation, the TimerResult's Incomplete() method will return true.
	Sleep(context.Context, time.Duration) TimerResult

	// Creates a new Timer instance, bound to this Clock.
	//
	// If the supplied Context is canceled, the timer will expire immediately.
	NewTimer(c context.Context) Timer
}

type Factory func(context.Context) Clock

type Timer interface {
	// GetC returns the underlying timer's channel.
	//
	// If the Timer is interrupted via Stop, its channel will block indefinitely.
	GetC() <-chan TimerResult

	// Reset configures the timer to expire after a specified duration.
	//
	// If the timer is already running, its previous state will be cleared and
	// this method will return true. The channel returned by GetC() will not
	// change due to Reset.
	Reset(d time.Duration) bool

	// Stop clears any timer tasking, rendering it inactive.
	//
	// Stop may be called on an inactive timer, in which case nothing will happen
	// If the timer is active, it will be stopped and this method will return
	// true.
	//
	// If a timer is stopped, its GetC channel will block indefinitely to avoid
	// erroneously unblocking goroutines that are waiting on it. This is
	// consistent with time.Timer.
	Stop() bool
}

type TimerResult struct {
	time.Time

	// Err, if not nil, indicates that After did not finish naturally and contains
	// the reason why.
	Err error
}