* its reference to it.
     *
     * If the output future is *not* done, then the task field will be cleared after the task runs
     * or after the output future is done, whichever comes first.
     */
    if (reason == OUTPUT_FUTURE_DONE) {
      this.task = null;
    }
  }

  @Override
  protected void interruptTask() {
    CombinedFutureInterruptibleTask<?> localTask = task;