Adding a hook (wrapper) for non-std stream reader in PyTorchStreamReader (#15551)
Summary:
To implement a stream is very annoying, since it is closely defined with the underlying storage streambuffer.
So in this PR, we add ReadAdapterInterface and PyTorchStreamReader will use it. We implement IStreamAdapter as a wrapper of std::istream. And keep the user interface unchanged.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/15551
Reviewed By: zrphercule
Differential Revision: D13568907
Pulled By: houseroad
fbshipit-source-id: 93708cb801248a6c101f35cb14d1631029365c3c
