*/
  void cleanUp() {
    if (threadStarted) {
      return;
    }

    Reference<?> reference;
    while ((reference = queue.poll()) != null) {
      /*
       * This is for the benefit of phantom references. Weak and soft references will have already
       * been cleared by this point.
       */
      reference.clear();
      try {
        ((FinalizableReference) reference).finalizeReferent();

   * world. Figure out what sort of space-time tradeoff we're actually going to get here with the
   * *Map variants. This class is particularly hard to benchmark, because the benefit is not only in
   * less allocation, but also having the GC do less work to scan the heap because of fewer
   * references, which is particularly hard to quantify.
   */

     * references (currently executing code, file descriptors).
     * 
     * Depending on the usage scenario, this may have some benefit as there won't be any delays for restablishing these
     * resources, however comes at the cost of having to properly release all SmbFile instances you no longer need.
     * 

    // the monitor with the guard satisfied. Therefore as soon as tearDownLatch is triggered, we
    // should be able to enter the monitor, and then we set the guard to satisfied for the benefit
    // of any remaining waiting threads.

    tearDownLatch.countDown();
    assertTrue(
        "Monitor still occupied in tearDown()",
        monitor.enter(UNEXPECTED_HANG_DELAY_MILLIS, TimeUnit.MILLISECONDS));

        // run() on the same thread that called execute() - such as in a thread pool, and think
        // that it was happening inline. As a side benefit, avoids holding on to the Thread object
        // longer than necessary.
        submitting = null;
      }
    }

    @SuppressWarnings("ShortCircuitBoolean")
    @Override
    public void run() {

    /*
     * Padding from 40 into 64 bytes, same size as cache line. Might be beneficial to add a fourth
     * long here, to minimize chance of interference between consecutive locks, but I couldn't
     * observe any benefit from that.
     */
    long unused1;
    long unused2;
    long unused3;

    PaddedLock() {
      super(false);
    }
  }

  private static class PaddedSemaphore extends Semaphore {

      tmp[5 - i] = hex.charAt(c & 0xF);
      c = (char) (c >> 4);
    }
    return String.copyValueOf(tmp);
  }

  // Fast matchers

  /** A matcher for which precomputation will not yield any significant benefit. */
  abstract static class FastMatcher extends CharMatcher {

    @Override
    public final CharMatcher precomputed() {
      return this;
    }

    @Override
    public CharMatcher negate() {