Multi-threading in PHP: Run emulated parallel threads with HTTP requests

This class can run emulated parallel threads with HTTP requests to the same server.

It can create parallel threads to run given PHP code by sending HTTP requests to an URL of the same server handled by a script that will execute a given function with optional arguments also passed in the HTTP request.

The class can also handle the HTTP requests to the emulated threads.

On the calling side, the class can check if the emulated thread has finished and retrieves the result as the HTTP response.