* Move sample-simple to Concurrent Mode
* Preload a query and lazy import Firestore
* more work on async/preloading
* demonstrate useTransition
* Update docs
* add note about experimental react build
* Update rollup config
Now that we're doing lazy imports with multiple chunks,
rollup needs to output to a directory
* docs fixes
* lazy import the rest of the SDKs
* remove some extra imports
* remove some extra imports