producer.doneProducing.await();
      if (drained == 0) {
        q.poll(); // not necessarily there if producer was interrupted
      }
    }
  }

  public void testDrainOverflow() throws InterruptedException {
    Queues.drain(new SynchronousQueue<>(), new ArrayList<>(), /* numElements= */ 0, MAX_DURATION);
  }

  public void testDrainUninterruptiblyOverflow() {