[PyTorch] [Model Tracer] Use c10::Synchronized<T> abstraction for mutex protected data (#73408)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/73408
Use the newly introduced `c10::Synchronized<T>` abstraction to enforce the use use of a mutex/lock on variables that should be protected for concurrent reads/modifications.
If reviewers think that this change is okay, I'll go ahead and change the other users in model tracer. This change is meant to show reviewers what the new code will look like.
ghstack-source-id: 150327550
Test Plan: Build model tracer.
Reviewed By: JacobSzwejbka
Differential Revision: D34465419
fbshipit-source-id: 9837479599e6301768c84f14b1df16a0c142cb8c
(cherry picked from commit cac88b5bb9496864d6103a9a9641be94ffb083bc)
