Summary:
This adds a new abstract class for a QuicAsyncUDPSocket abstraction that will be used by Mvfst instead of directly using folly objects. This will allow plugging in different implementations. The two that are currently planned are:
- folly-based
- pure libev based
Reviewed By: mjoras, sharmafb
Differential Revision: D50809223
fbshipit-source-id: 3852c9a7459b45d79e39ff24e7fc725e8703d3b8
