dillon1000/react

[Flight] Use AsyncLocalStorage to extend the scope of the cache to micro tasks (#25542)

This extends the scope of the cache and fetch instrumentation using
AsyncLocalStorage for microtasks. This is an intermediate step. It sets
up the dispatcher only once. This is unique to RSC because it uses the
react.shared-subset module for its shared state.

Ideally we should support multiple renderers. We should also have this
take over from an outer SSR's instrumented fetch. We should also be able
to have a fallback to global state per request where AsyncLocalStorage
doesn't exist and then the whole client-side solutions. I'm still
figuring out the right wiring for that so this is a temporary hack.