* [Blocks] Use native fetch
* Use the prototype
* Support arrayBuffer() and blob()
* ctor
* Simplify
* Use an expando
* Keep a map of formats
* Unused
* Remove unnecessary second property read
* Keep it simple
* Store the original thenable
* Rename ReactCache -> ReactCacheOld
We still use it in some tests so I'm going to leave it for now. I'll start making the new one in parallel in the react package.
* Add react/unstable-cache entry point
* Add react-data entry point
* Initial implementation of cache and data/fetch
* Address review