Have support multi process？ about purerpc

[standy66]

Hi! With multiprocessing we cannot correctly pass context_manager and setup_fn parameters to Server.add_service if they allocate system resources (connections to databases, for example). On Linux, you can run multiple instances of your server on the same port with SO_REUSEPORT option, this will effectively load balance the traffic on TCP connection level, if this is what you want. I will be updating example code shortly.

[boylegu]

oh～ Thanks a lot！