}
    assertEquals(1, count.get());
  }

  @J2ktIncompatible
  @GwtIncompatible // Thread
  @SuppressWarnings("ThreadPriorityCheck") // doing our best to test for races
  public void testSynchronizedSupplierThreadSafe() throws InterruptedException {
    Supplier<Integer> nonThreadSafe =
        new Supplier<Integer>() {
          int counter = 0;

          @Override
          public Integer get() {