*
 * <ul>
 *   <li>for an unnested {@code lock()} and {@code unlock()}, a cycle detecting lock takes 38ns as
 *       opposed to the 24ns taken by a plain lock.
 *   <li>for nested locking, the cost increases with the depth of the nesting:
 *       <ul>
 *         <li>2 levels: average of 64ns per lock()/unlock()
 *         <li>3 levels: average of 77ns per lock()/unlock()
 *         <li>4 levels: average of 99ns per lock()/unlock()

    }
    final ReentrantLock lock = this.lock;
    lock.lock();

    boolean satisfied = false;
    try {
      return satisfied = guard.isSatisfied();
    } finally {
      if (!satisfied) {
        lock.unlock();
      }
    }
  }

  /**
   * Enters this monitor if the guard is satisfied. Blocks at most the given time acquiring the
   * lock, but does not wait for the guard to be satisfied.

         * holding a lock. Still, it would be nice to avoid somehow.
         */
        lock.lock();
        try {
          currentFuture.cancel(mayInterruptIfRunning);
        } finally {
          lock.unlock();
        }
      }

      @Override
      public boolean isCancelled() {
        lock.lock();
        try {
          return currentFuture.isCancelled();

        drainRecencyQueue(segment);
      }
    }
  }

  static void drainRecencyQueue(Segment<?, ?> segment) {
    segment.lock();
    try {
      segment.cleanUp();
    } finally {
      segment.unlock();
    }
  }

  static void drainReferenceQueues(Cache<?, ?> cache) {
    if (hasLocalCache(cache)) {
      drainReferenceQueues(toLocalCache(cache));
    }

        drainRecencyQueue(segment);
      }
    }
  }

  static void drainRecencyQueue(Segment<?, ?> segment) {
    segment.lock();
    try {
      segment.cleanUp();
    } finally {
      segment.unlock();
    }
  }

  static void drainReferenceQueues(Cache<?, ?> cache) {
    if (hasLocalCache(cache)) {
      drainReferenceQueues(toLocalCache(cache));
    }

          "reached end of stream after reading " + read + " bytes; " + len + " bytes expected");
    }
  }

  /**
   * Discards {@code n} bytes of data from the input stream. This method will block until the full
   * amount has been skipped. Does not close the stream.
   *
   * @param in the input stream to read from
   * @param n the number of bytes to skip

              if (System.nanoTime() - t0 > timeout) {
                thrown.set(
                    new TimeoutException(
                        "timed out waiting for other threads to block"
                            + " synchronizing on supplier"));
                break;
              }
              Thread.yield();
            }
            count.getAndIncrement();

              if (System.nanoTime() - t0 > timeout) {
                thrown.set(
                    new TimeoutException(
                        "timed out waiting for other threads to block"
                            + " synchronizing on supplier"));
                break;
              }
              Thread.yield();
            }
            count.getAndIncrement();

 * the queue exceeds that value, the queue automatically removes its greatest element according to
 * its comparator (which might be the element that was just added). This is different from
 * conventional bounded queues, which either block or reject new elements when full.
 *
 * <p>This implementation is based on the <a
 * href="http://portal.acm.org/citation.cfm?id=6621">min-max heap</a> developed by Atkinson, et al.