Eh, it doesn't sound too bad. There's already a myriad of meta data (HTTP request headers) you need to process today if you want to be a good HTTP citizen, such as acknowledging Accept-Encoding, HTTP byte ranges, If-Modified-Since, X-Forwarded-For, X-Forwarded-Proto, etc; and sending correct response headers such as Cache-Control, Vary, and so on.
Having to write your app to understand that TLS 1.3 was used, and 0RTT was used, seems like a really really bad idea. The longer I'm in engineering, the more I realize that the number of people who understand the ramifications here is much smaller than the number who can throw together a TLS 1.3 listening HTTP server by following some dude's tutorial.
Framework support is not going to be enough. This seems like a bad, bad move.