title: Submit code for execution to all processes in a concurrent.futures.ProcessPool
body: <p>Context:</p>
  <ul>
  <li>A Python application server that uses a <code>concurrent.futures.process.ProcessPool</code> to execute code</li>
  <li>We sometimes want to hot reload imported code without restarting the entire server process</li>
  </ul>
  <p>(yes I know <code>importlib.reload</code> has <a href="https://docs.python.org/3/library/importlib.html#importlib.reload" rel="noreferrer">caveats</a>)</p>
  <p>To get this to work I imagine I would have to execute the <code>importlib.reload</code> in every <code>multiprocessing</code> process that is managed by the process pool.</p>
  <p>Is there a way to submit something to <strong>all</strong> processes in a process pool?</p>