) {
    setUp(protocol, mockWebServer)
    server.enqueue(
      MockResponse.Builder()
        .body(Buffer().write(ByteArray(Http2Connection.OKHTTP_CLIENT_WINDOW_SIZE + 1)))
        .build(),
    )
    server.enqueue(
      MockResponse(body = "abc"),
    )
    // Enqueue an additional response that show if we burnt a good prior response.
    server.enqueue(
      MockResponse(body = "XXX"),
    )

  private void growIfNeeded() {
    if (size > queue.length) {
      int newCapacity = calculateNewCapacity();
      Object[] newQueue = new Object[newCapacity];
      arraycopy(queue, 0, newQueue, 0, queue.length);
      queue = newQueue;
    }
  }

  /** Returns ~2x the old capacity if small; ~1.5x otherwise. */
  private int calculateNewCapacity() {
    int oldCapacity = queue.length;
    int newCapacity =

    delayNanos: Long,
  ) {
    lock.assertHeld()

    val queue = task.queue!!
    check(queue.activeTask === task)

    val cancelActiveTask = queue.cancelActiveTask
    queue.cancelActiveTask = false
    queue.activeTask = null
    busyQueues.remove(queue)

    if (delayNanos != -1L && !cancelActiveTask && !queue.shutdown) {
      queue.scheduleAndDecide(task, delayNanos, recurrence = true)
    }

  }

  static <E extends @Nullable Object> Queue<E> queue(Queue<E> queue, @CheckForNull Object mutex) {
    return (queue instanceof SynchronizedQueue) ? queue : new SynchronizedQueue<E>(queue, mutex);
  }

  static class SynchronizedQueue<E extends @Nullable Object> extends SynchronizedCollection<E>
      implements Queue<E> {

    SynchronizedQueue(Queue<E> delegate, @CheckForNull Object mutex) {

  }

  static <E extends @Nullable Object> Queue<E> queue(Queue<E> queue, @CheckForNull Object mutex) {
    return (queue instanceof SynchronizedQueue) ? queue : new SynchronizedQueue<E>(queue, mutex);
  }

  static class SynchronizedQueue<E extends @Nullable Object> extends SynchronizedCollection<E>
      implements Queue<E> {

    SynchronizedQueue(Queue<E> delegate, @CheckForNull Object mutex) {

    dispatcher.maxRequests = 2
    client.newCall(newRequest("http://a/1")).enqueue(callback)
    client.newCall(newRequest("http://b/1")).enqueue(callback)
    client.newCall(newRequest("http://c/1")).enqueue(callback)
    client.newCall(newRequest("http://a/2")).enqueue(callback)
    client.newCall(newRequest("http://b/2")).enqueue(callback)
    dispatcher.maxRequests = 4

  @Test
  fun connectionPooling_Async() {
    server.enqueue(MockResponse(body = "abc"))
    server.enqueue(MockResponse(body = "def"))
    server.enqueue(MockResponse(body = "ghi"))
    client.newCall(Request.Builder().url(server.url("/a")).build()).enqueue(callback)
    callback.await(server.url("/a")).assertBody("abc")
    client.newCall(Request.Builder().url(server.url("/b")).build()).enqueue(callback)

    ListenerCallQueue<Object> queue = new ListenerCallQueue<>();
    queue.addListener(listener, directExecutor());

    Multiset<Object> counters = ConcurrentHashMultiset.create();
    queue.enqueue(incrementingEvent(counters, listener, 1));
    queue.enqueue(THROWING_EVENT);
    queue.enqueue(incrementingEvent(counters, listener, 2));
    queue.enqueue(THROWING_EVENT);
    queue.enqueue(incrementingEvent(counters, listener, 3));

    ListenerCallQueue<Object> queue = new ListenerCallQueue<>();
    queue.addListener(listener, directExecutor());

    Multiset<Object> counters = ConcurrentHashMultiset.create();
    queue.enqueue(incrementingEvent(counters, listener, 1));
    queue.enqueue(THROWING_EVENT);
    queue.enqueue(incrementingEvent(counters, listener, 2));
    queue.enqueue(THROWING_EVENT);
    queue.enqueue(incrementingEvent(counters, listener, 3));

  @Test
  fun redirectToCachedResult() {
    server.enqueue(
      MockResponse.Builder()
        .addHeader("Cache-Control: max-age=60")
        .body("ABC")
        .build(),
    )
    server.enqueue(
      MockResponse.Builder()
        .code(HttpURLConnection.HTTP_MOVED_PERM)
        .addHeader("Location: /foo")
        .build(),
    )
    server.enqueue(
      MockResponse.Builder()
        .body("DEF")