return callable.toString();
              }
            });
    executor.execute(task);
    this.future = task;
  }

  private ClosingFuture(final AsyncClosingCallable<V> callable, Executor executor) {
    checkNotNull(callable);
    TrustedListenableFutureTask<V> task =
        TrustedListenableFutureTask.create(
            new AsyncCallable<V>() {
              @Override