}
    return returnValue;
  }

  // This is the old implementation of ExecutionList using a LinkedList.
  private static final class OldExecutionList {
    static final Logger log = Logger.getLogger(OldExecutionList.class.getName());
    final Queue<OldExecutionList.RunnableExecutorPair> runnables = Lists.newLinkedList();
    boolean executed = false;

    public void add(Runnable runnable, Executor executor) {