title: How to remove old queued tasks in ThreadPoolExecutor and insert new tasks instead?
body: <p>I load a lot of images form internet with a ThreadPoolExecutor.</p>
  
  <p>When new images found, I need to render it first, in that case I want to abandon the old tasks which are still queued in the ThreadPoolExecutor and added these new items to download.</p>
  
  <p>I found there are no "clear queue" method in ThreadPoolExecutor, and "purge" method sounds like not good for this.</p>
  
  <p>What should I do?</p>
  
  <p>I just thought to call "shutdown" of this executor and recreate a new one to do this, not sure whether it is appropriate.</p>