}

  @GwtIncompatible // concurrency

  public void testConcurrentAdvance() throws Exception {
    FakeTicker ticker = new FakeTicker();

    int numberOfThreads = 64;
    runConcurrentTest(
        numberOfThreads,
        () -> {
          // adds two nanoseconds to the ticker
          ticker.advance(1L);
          Thread.sleep(10);
          ticker.advance(1L);
          return null;

  }

  @GwtIncompatible // concurrency

  public void testConcurrentAdvance() throws Exception {
    FakeTicker ticker = new FakeTicker();

    int numberOfThreads = 64;
    runConcurrentTest(
        numberOfThreads,
        () -> {
          // adds two nanoseconds to the ticker
          ticker.advance(1L);
          Thread.sleep(10);
          ticker.advance(1L);
          return null;