feat: partial prerendering

[hi-ogawa]

This looks like react-dom ssr feature, so I can (should?) experiment without rsc first? (EDIT: done in https://github.com/hi-ogawa/experiments/tree/main/ppr)

prerender/resume is only available on experimental, so probably we should put off a little.

Again, demo on cloudflare is working but not on vercel

• https://demo-rsc-prerender.pages.dev/ppr

todo

• minimal demo without RSC feat: add PPR demo experiments#18
• integrate RSC
  • for now, separate it from prerender
  • for now, just for ssr and not for flight request (like Next.js?)
  • can we get away without async context? probably we can toggle postpone based on global, just like what I did for ssg process.env["REACT_SERVER_PRERENDER"] = "1".
  • how to read back prelude and postponed during runtime?
    • we can go with globalThis injection to the server entry...
  • cannot minify after build?
  • deal with compression and stream?
    • local preview
    • cf (actually it's working on wrangler pages dev while wrangler dev didn't work in https://github.com/hi-ogawa/experiments/tree/main/ppr due to compression)
    • vercel
• port next.js demo? https://github.com/vercel-labs/next-partial-prerendering
• test

[hi-ogawa]

• superseded by feat: partial prerendering #501