class Async::Container::Notify::Pipe

def before_spawn(arguments, options)
	environment = environment_for(arguments)
	
	# Use `notify_pipe` option if specified:
	if notify_pipe = options.delete(:notify_pipe)
		options[notify_pipe] = @io
		environment[NOTIFY_PIPE] = notify_pipe.to_s
	
	# Use stdout if it's not redirected:
	# This can cause issues if the user expects stdout to be connected to a terminal.
	# elsif !options.key?(:out)
	# 	options[:out] = @io
	# 	environment[NOTIFY_PIPE] = "1"
	
	# Use fileno 3 if it's available:
	elsif !options.key?(3)
		options[3] = @io
		environment[NOTIFY_PIPE] = "3"
	
	# Otherwise, give up!
	else
		raise ArgumentError, "Please specify valid file descriptor for notify_pipe!"
	end
end