It's easy way to call asynchronous request in PHP used magic method __call, PHP sockets and HTTP header. There we can call any php function where isn't a response(callback), so, function dosen't have a return.
Just download or pull and let's try!
A main idea is from Mark Turansky blog(http://blog.markturansky.com/archives/205), where author wrote the idea - how to use asynchronous request.