As I understand it, the join() method merge/composes/combines the results from all subtasks. A simple example I saw was summing the numbers from 1 to N and the subtasks would simply sum a range of such numbers -- obtaining the final result very naturally involved summing each subtask's result to indeed get the right answers.
However, what if the results could not be combined via simple addition? Is there a way of specifying both a custom class for a result and a custom method of merging these results?
