pytorch

4997c38a - [Gradient Compression] Don't provide default values in GradBucket constructor (#53102)

[Gradient Compression] Don't provide default values in GradBucket constructor (#53102) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/53102 In `GradBucket` constructor, `offsets`, `lengths`, and `sizes_vec` are optional arguments and could possibly be empty. It will be safe to remove the default values. ghstack-source-id: 122833603 Test Plan: waitforbuildbot Reviewed By: rohan-varma Differential Revision: D26748199 fbshipit-source-id: 2e3bcd1b732851919a64bbbd20fe85e77a616fe3