/**
     * Records cache hits. This should be called when a cache request returns a cached value.
     *
     * @param count the number of hits to record
     * @since 11.0
     */
    void recordHits(int count);

    /**
     * Records cache misses. This should be called when a cache request returns a value that was not
     * found in the cache. This method should be called by the loading thread, as well as by threads

      new Runnable() {
        @Override
        public void run() {}
      };
  boolean called = false;

  private void assertSingleCallWithCorrectParameters(
      Runnable command, long initialDelay, long delay, TimeUnit unit) {
    assertFalse(called); // only called once.
    called = true;
    assertEquals(INITIAL_DELAY, initialDelay);
    assertEquals(DELAY, delay);
    assertEquals(UNIT, unit);

   * convenient. It is invoked exactly once on service shutdown, even when {@link #stopAsync} is
   * called multiple times.
   *
   * <p>When this method is called {@link #state()} will return {@link State#STOPPING}, which is the
   * external state observable by the caller of {@link #stopAsync}.
   *
   * @since 27.0
   */
  @ForOverride
  protected void doCancelStart() {}

  @CanIgnoreReturnValue

    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

    // Finish the task by unblocking the task latch.  Then wait for the
    // listener to be called by blocking on the listener latch.
    taskLatch.countDown();
    assertEquals(25, task.get().intValue());
    assertTrue(listenerLatch.await(5, TimeUnit.SECONDS));
    assertTrue(task.isDone());

  }

  public void testFutureGetThrowsWrappedError() throws Exception {
    Error error = new Error();
    inputFuture.setException(error);
    // Verify that get throws an ExecutionException, caused by an Error, when
    // the callback is called.
    listener.assertException(error);
  }

  public void testAddListenerAfterCallback() throws Throwable {
    inputFuture.set(VALID_INPUT_DATA);

  }

  /**
   * Wraps the given callable such that for the duration of {@link Callable#call} the thread that is
   * running will have the given name.
   *
   * @param callable The callable to wrap
   * @param nameSupplier The supplier of thread names, {@link Supplier#get get} will be called once
   *     for each invocation of the wrapped callable.
   */
  @J2ktIncompatible
  @GwtIncompatible // threads

    // JVM shutdown will not be prevented from exiting after this service has stopped or failed.
    // Technically this listener is added after start() was called so it is a little gross, but it
    // is called within doStart() so we know that the service cannot terminate or fail concurrently

      /*
       * requireNonNull is safe because we don't null out `sequencer` except:
       *
       * - after the requireNonNull call below. (And this object has its Runnable.run override
       *   called only once, just as it has its Executor.execute override called only once.)
       *
       * - if we return immediately from `execute` (in which case we never get here)
       *

      new Runnable() {
        @Override
        public void run() {}
      };
  boolean called = false;

  private void assertSingleCallWithCorrectParameters(
      Runnable command, long initialDelay, long delay, TimeUnit unit) {
    assertFalse(called); // only called once.
    called = true;
    assertEquals(INITIAL_DELAY, initialDelay);
    assertEquals(DELAY, delay);
    assertEquals(UNIT, unit);

    @CheckForNull
    protected EndpointPair<N> computeNext() {
      while (true) {
        /*
         * requireNonNull is safe because visitedNodes isn't cleared until this method calls
         * endOfData() (after which this method is never called again).
         */
        requireNonNull(visitedNodes);
        while (successorIterator.hasNext()) {
          N otherNode = successorIterator.next();