Page Speed Tip: Defer time consuming processes after sending the page output
Recently I have written a PHP class to try server analytics. But using the UAMP, script has to wait for response from Google's servers in order to close the connection. Even if the response took less than 100ms, still it's unnecessary time for client to wait and show loading spinner and block page render.
There is a space for optimisation: closing connection early and present the client with the response before the script finishes it's run.