class Async::Reactor

def run(*args, &block)
	raise RuntimeError, 'Reactor has been closed' if @selector.nil?
	
	@stopped = false
	
	initial_task = self.async(*args, &block) if block_given?
	
	@timers.wait do |interval|
		# logger.debug(self) {"@ready = #{@ready} @running = #{@running}"}
		
		if @ready.any?
			# running used to correctly answer on `finished?`, and to reuse Array object.
			@running, @ready = @ready, @running
			
			@running.each do |fiber|
				fiber.resume if fiber.alive?
			end
			
			@running.clear
			
			# if there are tasks ready to execute, don't sleep.
			if @ready.any?
				interval = 0
			else
				# The above tasks may schedule, cancel or affect timers in some way. We need to compute a new wait interval for the blocking selector call below:
				interval = @timers.wait_interval
			end
		end
		
		# As timeouts may have been updated, and caused fibers to complete, we should check this.
		if interval.nil?
			if self.finished?
				# If there is nothing to do, then finish:
				return initial_task
			end
		elsif interval < 0
			# We have timers ready to fire, don't sleep in the selctor:
			interval = 0
		end
		
		# logger.debug(self) {"Selecting with #{@children&.count} children with interval = #{interval.inspect}..."}
		if monitors = @selector.select(interval)
			monitors.each do |monitor|
				monitor.value.resume
			end
		end
	end until @stopped
	
	return initial_task
ensure
	logger.debug(self) {"Exiting run-loop because #{$! ? $! : 'finished'}."}
	
	@stopped = true
end