Moved SlicedBufferedReader to utils and renamed to _ReaderView.
It no longer depends on file handles and is a pure wrapper. This makes it general enought to handle non io stream objects like fsspec's.
Should help with #98386
Pull Request resolved: https://github.com/pytorch/pytorch/pull/99167
Approved by: https://github.com/wz337
This PR moves nested_tensors to torch.distributed.checkpoint. This is a pre-req for enabling 2D checkpoint.
This flattens sharded tensors in state_dict. It is used when saving and loading FSDP SHARDED_STATE_DICT.
Docstring, individual and integration test will be added in the following PRs.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/89501
Approved by: https://github.com/wanchaol
