assertFalse(future.isDone());
    assertFalse(future.isCancelled());

    CountDownLatch successLatch = new CountDownLatch(1);

    // Run cancellation in a separate thread as an extra thread-safety test.
    new Thread(
            () -> {
              assertThrows(CancellationException.class, future::get);
              successLatch.countDown();
            })
        .start();

    assertFalse(future.isDone());
    assertFalse(future.isCancelled());

    CountDownLatch successLatch = new CountDownLatch(1);

    // Run cancellation in a separate thread as an extra thread-safety test.
    new Thread(
            () -> {
              assertThrows(CancellationException.class, future::get);
              successLatch.countDown();
            })
        .start();

     *            the length of time to sleep in milliseconds
     * @throws InterruptedRuntimeException
     *             if any thread has interrupted the current thread.
     */
    public static void sleep(final long millis) {
        if (millis < 1L) {
            return;
        }
        try {
            Thread.sleep(millis);
        } catch (final InterruptedException e) {
            throw new InterruptedRuntimeException(e);
        }

  class Interruptenator extends Thread {
    final AtomicBoolean shutdown;

    Interruptenator(Thread interruptee) {
      this(interruptee, new AtomicBoolean(false));
    }

    @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
    Interruptenator(Thread interruptee, AtomicBoolean shutdown) {
      super(
          new Runnable() {

        // Test thread safety with concurrent operations
        final int threadCount = 10;
        Thread[] threads = new Thread[threadCount];
        final boolean[] results = new boolean[threadCount];

        for (int i = 0; i < threadCount; i++) {
            final int index = i;
            threads[i] = new Thread(() -> {
                String thumbnailId = "concurrent-" + index;

        }
      }
    } finally {
      if (interrupted) {
        Thread.currentThread().interrupt();
      }
    }
  }

  /** Invokes {@code toJoin.}{@link Thread#join() join()} uninterruptibly. */
  @J2ktIncompatible
  @GwtIncompatible // concurrency
  public static void joinUninterruptibly(Thread toJoin) {
    boolean interrupted = false;
    try {
      while (true) {
        try {

            // Start all threads
            for (Thread thread : threads) {
                thread.start();
            }

            // Wait for all threads to complete
            for (Thread thread : threads) {
                try {
                    thread.join();
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                    fail("Thread interrupted");

  }

  @SuppressWarnings("ThreadPriorityCheck") // TODO: b/175898629 - Consider onSpinWait.
  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:

      assertThat(e).hasMessageThat().isEqualTo("Cannot get() on a pending future.");
    }
  }

  static void verifyThreadWasNotInterrupted() {
    // There is no thread interruption in GWT, so there's nothing to do.
  }

  static void clearInterrupt() {
    // There is no thread interruption in GWT, so there's nothing to do.
  }

  static <V extends @Nullable Object> V getDoneFromTimeoutOverload(Future<V> future)

                            session.acquire();
                            Thread.yield(); // Increase chance of race conditions
                            session.release();
                        } else {
                            session.acquire();
                            // Hold for a bit
                            Thread.sleep(1);
                            session.release();
                        }