* interrupting thread. In theory, interruptTask() should be very fast, but due to
         * InterruptibleChannel and JavaLangAccess.blockedOn(Thread, Interruptible), it isn't
         * predictable what work might be done. (e.g., close a file and flush buffers to disk). To
         * protect ourselves from this, we park ourselves and tell our interrupter that we did so.

  private static final long SMALL_TIMEOUT_MILLIS = 10;

  /** How long to wait when determining that a thread is blocked if we expect it to be blocked. */
  private static final long EXPECTED_HANG_DELAY_MILLIS = 75;

  /**
   * How long to wait when determining that a thread is blocked if we DON'T expect it to be blocked.
   */
  private static final long UNEXPECTED_HANG_DELAY_MILLIS = 10000;

  /**

   * specified access policy.
   *
   * @param capacity the capacity of this queue
   * @param fair if {@code true} then queue accesses for threads blocked on insertion or removal,
   *     are processed in FIFO order; if {@code false} the access order is unspecified.
   * @throws IllegalArgumentException if {@code capacity} is less than 1
   */

            }
            throw new RejectedExecutionException();
          }
        };
    SequentialExecutor executor = new SequentialExecutor(delegate);
    ExecutorService blocked = newCachedThreadPool();
    Future<?> first =
        blocked.submit(
            new Runnable() {
              @Override
              public void run() {
                executor.execute(Runnables.doNothing());
              }

    sendRequest(methodName, arguments);
    assertEquals(expected, getResponse(methodName).getThrowable().getClass());
  }

  /**
   * Causes this thread to call the named method, and asserts that this thread becomes blocked on
   * the lock-like object. The lock-like object must have a method equivalent to {@link
   * java.util.concurrent.locks.ReentrantLock#hasQueuedThread(Thread)}.
   */

    long timeout = SECONDS.toNanos(60);

    Supplier<Boolean> supplier =
        new Supplier<Boolean>() {
          boolean isWaiting(Thread thread) {
            switch (thread.getState()) {
              case BLOCKED:
              case WAITING:
              case TIMED_WAITING:
                return true;
              default:
                return false;
            }
          }

  @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
  void awaitTimedWaiting(Thread thread) {
    while (true) {
      switch (thread.getState()) {
        case BLOCKED:
        case NEW:
        case RUNNABLE:
        case WAITING:
          Thread.yield();
          break;
        case TIMED_WAITING:
          return;
        case TERMINATED:

    sendRequest(methodName, arguments);
    assertEquals(expected, getResponse(methodName).getThrowable().getClass());
  }

  /**
   * Causes this thread to call the named method, and asserts that this thread becomes blocked on
   * the lock-like object. The lock-like object must have a method equivalent to {@link
   * java.util.concurrent.locks.ReentrantLock#hasQueuedThread(Thread)}.
   */

    // This should wake up waiter1 and cause the waiter1 node to be removed.
    waiter1.interrupt();

    waiter1.join();
    waiter2.awaitWaiting(); // should still be blocked

    LockSupport.unpark(waiter2); // spurious wakeup
    waiter2.awaitWaiting(); // should eventually re-park

    future.set(null);
    waiter2.join();
  }

  static void awaitWaiting(Thread t) {
    while (true) {
      Thread.State state = t.getState();
      switch (state) {
        case RUNNABLE:
        case BLOCKED:
          Thread.yield();
          break;
        case WAITING:
          return;
        default:
          throw new AssertionError("unexpected state: " + state);
      }
    }
  }