class Async::Scheduler

def run_once(timeout = nil)

@returns [Boolean] Whether there is more work to do.
@parameter timeout [Float | Nil] The maximum timeout, or if nil, indefinite.

@asynchronous Must be invoked from blocking (root) fiber.
@public Since *Async v1*.

Run one iteration of the event loop. 
def run_once(timeout = nil)
	Kernel.raise "Running scheduler on non-blocking fiber!" unless Fiber.blocking?
	
	if self.finished?
		self.stop
	end
	
	# If we are finished, we stop the task tree and exit:
	if @children.nil?
		return false
	end
	
	return run_once!(timeout)
end