Pause accepting new connections but continue serving existing ones

[phoad]

In one of the projects that will use RSocket, there are two functions to pause or stop the server, which is to be replaced by RSocketServer. (see: BaseThriftServer)

• stop
• stopListening

Stop is just calling rsocketServer->showdownAndWait().

But we miss the stopListening functionality which should only pause accepting new connections and continue serving the existing ones.

I wonder if we should have functionality to pause accepting new connections or creating new streams, i.e. if we have a higher level logic that checks the load and tries to save the server from getting overloaded.