Compression Dictionaries draft 04

FYI, draft 04 of the compression dictionaries spec was just released:
https://datatracker.ietf.org/doc/draft-ietf-httpbis-compression-dictionary/

The changes since draft 03 are:

- Added link relation ("compression-dictionary")
- Moved the dictionary hash into the response payload and removed the
"Compression-Dictionary" response header
- Changed content-encodings to "dcb" and "dcz"
- Specified the compression window settings for Zstandard and Brotli

We're converging on a final spec and the Chrome origin trials to-date have
been extremely positive.

There is one remaining discussion topic that I'm aware of which is around
the compression algorithms that we spec and if we should collapse to a
single algorithm and manage fragmentation at the spec level:
https://github.com/httpwg/http-extensions/issues/2756

If you're aware of any other issues or have concerns with something else in
the spec, please let us know. Otherwise we're hoping to come to an
agreement on the compression algorithms and then move towards last call and
RFC.

Thanks,

-Pat