NewDispatcher create a new Dispatcher with a given number of workers.

RegisterPostActivityHook registers an ActivityHook in the list of ActivityHooks that will be triggered after a workflow activity.

RegisterPreActivityHook registers an ActivityHook in the list of ActivityHooks that will be triggered before a workflow activity.

Dispatcher concern is polling executions task and dispatch them across available workers It has to acquire a lock on the execution task as other distributed dispatchers can try to do the same If it gets the lock, it instantiates an execution task and push it to workers pool If it receives a message from shutdown channel, it has to spread the shutdown to workers.

An ActivityHook is a function that could be registered as pre or post activity hook and which is called respectively just before or after a workflow activity TaskExecution.