## Summary
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Explain the **motivation** for making this change. What existing problem
does the pull request solve?
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A proposed fix for the bug described in
https://github.com/facebook/react/issues/25967
## How did you test this change?
See the issue linked above, test scenario included in the code sandbox:
https://codesandbox.io/s/fervent-ives-0vm9es?file=/src/App.jsx
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This setting is an incremental path to the next Flow version enforcing
type annotations on most functions (except some inline callbacks).
Used
```
node_modules/.bin/flow codemod annotate-functions-and-classes --write .
```
to add a majority of the types with some hand cleanup when for large
inferred objects that should just be `Fiber` or weird constructs
including `any`.
Suppressed the remaining issues.
Builds on #25918
* Facebook -> Meta in copyright
rg --files | xargs sed -i 's#Copyright (c) Facebook, Inc. and its affiliates.#Copyright (c) Meta Platforms, Inc. and affiliates.#g'
* Manual tweaks
* Move useSyncExternalStore shim to a nested entrypoint
Also renames `useSyncExternalStoreExtra` to
`useSyncExternalStoreWithSelector`.
- 'use-sync-external-store/shim' -> A shim for `useSyncExternalStore`
that works in React 16 and 17 (any release that supports hooks). The
module will first check if the built-in React API exists, before
falling back to the shim.
- 'use-sync-external-store/with-selector' -> An extended version of
`useSyncExternalStore` that also supports `selector` and `isEqual`
options. It does _not_ shim `use-sync-external-store`; it composes the
built-in React API. **Use this if you only support 18+.**
- 'use-sync-external-store/shim/with-selector' -> Same API, but it
composes `use-sync-external-store/shim` instead. **Use this for
compatibility with 16 and 17.**
- 'use-sync-external-store' -> Re-exports React's built-in API. Not
meant to be used. It will warn and direct users to either the shim or
the built-in API.
* Upgrade useSyncExternalStore to alpha channel
Jelle Voost
Jan Kassens
Andrew Clark