* will not be released until that submitted task is also complete.
   *
   * <p>If a task is {@linkplain Thread#interrupt interrupted} while a task is running:
   *
   * <ol>
   *   <li>execution will not stop until the task queue is empty.
   *   <li>tasks will begin execution with the thread marked as not interrupted - any interruption
   *       applies only to the task that was running at the point of interruption.

    final T value;
    final int rank;

    Composite(T value, int rank) {
      this.value = value;
      this.rank = rank;
    }

    // natural order is by rank only; the test will compound() this with the
    // order of 't'.
    @Override
    public int compareTo(Composite<T> that) {
      return Ints.compare(rank, that.rank);
    }

    final T value;
    final int rank;

    Composite(T value, int rank) {
      this.value = value;
      this.rank = rank;
    }

    // natural order is by rank only; the test will compound() this with the
    // order of 't'.
    @Override
    public int compareTo(Composite<T> that) {
      return Ints.compare(rank, that.rank);
    }