timer

type HV struct {
	Height uint32
	View   byte
}

type Timer interface {
	// Now returns current time.
	Now() time.Time
	// Reset
	Reset(s HV, d time.Duration)
	// Sleep stops execution for duration d.
	Sleep(d time.Duration)
	// Extend extends current timer with duration d.
	Extend(d time.Duration)
	// Stop stops timer.
	Stop()
	// HV returns current height and view set for the timer.
	HV() HV
	// C returns channel for timer events.
	C() <-chan time.Time
}