(to be transparent - I'm a Cloudflare engineer)

The behavior isn't entirely the same and reaching 100% parity is a non-goal, but there are a few things to note.

This is still a very early implementation and there are undoubtedly issues with the implementation that weren't covered in next's original test suite (and thus not inherited) while not being obvious enough to pop up with all the apps we've tried so far.

As for why it's so much smaller, by building on top of Vite and their react + rsc plugins there is a whole lot of code that we don't need to write. That's where a significant portion of the LOC difference comes from.