pytorch

76bccfb2 - [15/n] [torch/elastic] Introduce _RendezvousStateHolder (#56538)

[15/n] [torch/elastic] Introduce _RendezvousStateHolder (#56538) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/56538 This PR introduces the `_RendezvousStateHolder` interface and its accompanying `_BackendRendezvousStateHolder` type that is responsible for synchronizing the local rendezvous state with the other nodes. ghstack-source-id: 127684796 Test Plan: Run the existing and new unit tests. Reviewed By: tierex Differential Revision: D27892600 fbshipit-source-id: a55d884a1f9b0d742787be4dff4271e076c08962