final @Nullable Listener listeners() {
    return listenersField;
  }

  /** Releases all threads in the {@link #waitersField} list, and clears the list. */
  final void releaseWaiters() {
    Waiter head = gasWaiters(Waiter.TOMBSTONE);
    for (Waiter currentWaiter = head; currentWaiter != null; currentWaiter = currentWaiter.next) {
      currentWaiter.unpark();
    }
  }

    @RetainedLocalRef AbstractFuture<?> future = param;

    @RetainedLocalRef Listener next = null;
    outer:
    while (true) {
      future.releaseWaiters();
      /*
       * We call interruptTask() immediately before afterDone() so that migrating between the two
       * can be a no-op.
       */
      if (callInterruptTask) {
        future.interruptTask();