title: Drop oldest item from python's Queue.Queue (with synchronization)
body: <p>Can I configure <code>Queue.Queue</code> so that it always accepts new items, and simply drops the oldest item if the queue is full?</p>
  
  <p>If not, is there another queue class in the standard library that can do this?</p>
  
  <p>(I cannot use deque because I have a producer/consumer setup where I need synchronization.)</p>