protocol: Protocol,
    mockWebServer: MockWebServer,
  ) {
    setUp(protocol, mockWebServer)
    val responseDequeuedLatches =
      listOf(
        // No synchronization for the last request, which is not canceled:
        CountDownLatch(1),
        CountDownLatch(0),
      )
    val requestCanceledLatches =
      listOf(
        CountDownLatch(1),

 *
 * <p>If {@code null} is passed as the {@code mutex} parameter to any of this class's top-level
 * methods or inner class constructors, the created object uses itself as the synchronization mutex.
 *
 * <p>This class should be used by other collection classes only.
 *
 * @author Mike Bostock
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
/*

   * one input completes with result X and another later with result Y, for Y to come before X in
   * the output future list. (Such races are impossible to solve without global synchronization of
   * all future completions. And they should have little practical impact.)
   *
   * <p>Cancelling a delegate future propagates to input futures once all the delegates complete,