Section 1.2 cites as a problem:
Classic HTTP CONNECT requests cannot carry in-stream metadata. For example, the WRAP_UP capsule [I-D.schinazi-httpbis-wrap-up] cannot be used with Classic HTTP CONNECT.
We then define DATA and FINAL_DATA capsules, each of which also cannot carry in-stream metadata. That's fine, since you can interleave other capsules, but as far as I can tell, that's mostly just hinted at in the document (e.g. references to other capsules between DATA capsules).
Perhaps we should have a brief mention that future metadata should be conveyed by extending with additional capsules per RFC 9297, just to make that extensibility pathway clear.
Section 1.2 cites as a problem:
We then define DATA and FINAL_DATA capsules, each of which also cannot carry in-stream metadata. That's fine, since you can interleave other capsules, but as far as I can tell, that's mostly just hinted at in the document (e.g. references to other capsules between DATA capsules).
Perhaps we should have a brief mention that future metadata should be conveyed by extending with additional capsules per RFC 9297, just to make that extensibility pathway clear.