exitLatch.await();
    assertTrue(interruptedExceptionThrown.get());
  }

  @J2ktIncompatible
  @GwtIncompatible // blocking wait
  public void testRunIdempotency() throws Exception {
    final int numThreads = 10;
    final ExecutorService executor = Executors.newFixedThreadPool(numThreads);
    for (int i = 0; i < 1000; i++) {