upcxx::rpc function shipping

[BrianS]

As I mull this one over more, this has to get handled in the Progress API.

Either the user threads call upcxx::progress (blocking or non-blocking?), or there is a queue that a user thread must dequeue and execute the function, or the user has allocated a thread (or threads) to execute upcxx::rpc calls. The latter is trickier since the rpc function needs to be anonymous.

It might be that a user can delegate progress threads to upcxx at the team level, with the contract stating that members of a team can execute rpc calls for other threads in the team.

[Amir Kamil]

I think this has been resolved by our definition of the Progress API.

[Amir Kamil]

Closing under the assumption this has been resolved.