Details
Description
Recently, I saw some use cases of AMRMClient(Async). The painful thing is that the main non-daemon thread has to sit in a dummy loop to prevent AM process exiting before all the tasks are done, while unregistration is triggered on a separate another daemon thread by callback methods (in particular when using AMRMClientAsync). IMHO, it should be beneficial to add a waitFor method to AMRMClient(Async) to block the AM until unregistration or user supplied check point, such that users don't need to write the loop themselves.