class Async::Timeout

@returns [Numeric] The new time at which the timeout will occur.
@parameter duration [Numeric] The duration to adjust the timeout by, in seconds.

The duration is relative to the timeout time, e.g. adjusting the timeout by 5 increases the current duration by 5 seconds.

Adjust the timeout by the specified duration.

def adjust(duration)
	self.reschedule(time + duration)
end