return "setFuture=[" + delegate + "]";
    }
    return null;
  }

  private void addDoneString(StringBuilder builder) {
    try {
      V value = getDone(this);
      builder.append("SUCCESS, result=[").append(value).append("]");
    } catch (ExecutionException e) {
      builder.append("FAILURE, cause=[").append(e.getCause()).append("]");
    } catch (CancellationException e) {
      builder.append("CANCELLED");

    // then we know it must have given a pending toString value earlier. If not, then the future
    // completed after the timeout expired, and the message might be success.
    if (isDone()) {
      throw new TimeoutException(message + " but future completed as timeout expired");
    }
    throw new TimeoutException(message + " for " + futureToString);
  }

  /**