Here is the problem:

• iOS: We need to run Reanimated 4 on the new achitecture to get decent performance.
• Android: We cannot use the new architecture yet (there are unsolved performance problems), so we need to use Reanimated 3.

How can we have two versions of a native library at once? Well...

• Require Reanimated 4 normally through package.json.
• Require Reanimated 3 indirectly through this r3-hack shim package.
• Use react-native.config.js to override the native module with Reanimated 3.
• Tell babel.config.js to use the right plugin based on platform.
• Hack metro.config.js to resolve 'react-native-reanimated' to this package's exported paths on Android.

Super sketchy, but it works!