title: most simple way to start a new process/thread in PHP
body: <p>Scenario:  </p>
  
  <ol>
  <li>Shared hosting, so no ability to install new extensions + no CRON</li>
  <li>A submitted request needs to perform some heavy processes. </li>
  <li>I want the answer to the client to go as fast as possible, and the heavy lifting to continue immediately, but not stop the client. </li>
  <li>can be on a new  thread (if it is possible) also no problem with starting a new process.</li>
  </ol>
  
  <p>What is the best way to do this?</p>