OSC flooding. How to prevent?

My application receives OSC messages from a machine vision server.
At times, too big messages come in too fast.

I’d like to stop listening to incoming messages while processing one, but I can’t find a way to pause my OSC server.
I see there’s a Stop command I can issue (tooltip says: stop and tidy up network socket). But, how do I re-start the thing!?

In C++ I’d like to use a CriticalSection object or something like that. What’s the best practice with Blueprints?