pytorch

b3dd8cde - [1/n] [torch/elastic] Introduce `DynamicRendezvousHandler` and `RendezvousBackend`. (#55635)

[1/n] [torch/elastic] Introduce `DynamicRendezvousHandler` and `RendezvousBackend`. (#55635) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/55635 This diff introduces the `DynamicRendezvousHandler` type as a stub implementation and its accompanying `RendezvousBackend` interface. `DynamicRendezvousHandler` is intended to be a backend-agnostic type that will contain the core (bulk) logic of rendezvous handling. Any backend specific operation will be delegated to a concrete subclass of `RendezvousBackend` (e.g. `C10dRendezvousBackend` - see D27654492) that is passed as a constructor argument to `DynamicRendezvousHandler`. ghstack-source-id: 126304697 Test Plan: Run the existing and newly-introduced unit/integration tests. Reviewed By: tierex Differential Revision: D27654478 fbshipit-source-id: 9fc89a6e4cb308971c65b29a7c5af7ae191f70c5