Message trigger of task executer

Hi guys, I want to understand the exact correct use of the return inside the code of the trigger event:
e.g. if I call a subtask which is treated by the message trigger then i put at the end return(ts), where ts is the tasksequence; if the message trigger answers to an explicit message to be performed then there will be a dispatchtasksequence(ts) and then a return 0.
What is the correct mode to operate in the different cases, for instance may the trigger function simply return void and in which cases?
Thanks very much in advance to anyone who will answer me.