Asyncronous work

I've always used a library based on this article:
http://blog.markturansky.com/archives/205

It sends it using fsockopen and just doesn't wait for a response back.

We have to submit lead data to a crm and use this method after the user submits the form and it's successful. That takes up to about 4 seconds so we send it using the above method and it's instant and the user doesn't have to wait.