class Async::IO::Threads

def async(parent: (@parent or Task.current))
	parent.async do
		thread = ::Thread.new do
			yield
		end
		
		thread.join
	rescue Stop
		if thread&.alive?
			thread.raise(Stop)
		end
		
		begin
			thread.join
		rescue Stop
			# Ignore.
		end
	end
end