Support Offline Tensors through ONNXIFI layer
Summary:
Previous import was b2ec1a8041879b7be98d81387a14cae895f952f4
Included changes:
- **[97fe555](https://github.com/houseroad/foxi/commit/97fe555)**: Add deferred weight reader pointer when initializing the graph (#15) <Yinghai Lu>
- **[ba2faf7](https://github.com/houseroad/foxi/commit/ba2faf7)**: Add status and timeout to events (#14) <Jack Montgomery>
Test Plan: kicksandcastle
Reviewed By: ipiszy
Differential Revision: D18231697
fbshipit-source-id: 7566e2438d2b57f0feaadcd51f55a03552adeab9
