Future<?> possiblyIgnoredError = serializer.submitAsync(firstCallable, directExecutor());
    TestCallable secondCallable = new TestCallable(immediateVoidFuture());
    ListenableFuture<@Nullable Void> secondFuture =
        serializer.submitAsync(secondCallable, directExecutor());
    TestCallable thirdCallable = new TestCallable(immediateVoidFuture());
    @SuppressWarnings({"unused", "nullness"})

    assertThat(runnableFuture).isInstanceOf(TrustedListenableFutureTask.class);
    assertTrue(runnableFuture.isDone());
    assertTrue(runnable.run);

    ListenableFuture<String> callableFuture = e.submit(new TestCallable());
    assertThat(callableFuture).isInstanceOf(TrustedListenableFutureTask.class);
    assertTrue(callableFuture.isDone());
    assertEquals("foo", callableFuture.get());

    TestRunnable runnable2 = new TestRunnable();

        controller.delayMillisAfterProcessing = 0L;
        controller.delayMillisForWaitingNewUrl = 0L;
        controller.delayMillisAtNoUrlInQueue = 0L;

        final Callable<Integer> testCallable = new Callable<Integer>() {
            public Integer call() throws Exception {
                CrawlingParameterUtil.setUrlQueue(q);
                controller.delayBeforeProcessing();
                return 0;