Code change:
method, and trailer fields for metadata collected while sending the payload. <del> A server responds to a client's request by sending one or more HTTP </del> <ins> A server responds to a client's request by sending one or more </ins> <del> messages, each including a success or error code (status.codes).  The response might also contain header fields for server information, resource metadata, and representation metadata (header.and.trailer.fields), a payload body (payload.body) to be interpreted in accordance with the status code, and trailer fields for metadata collected while sending the payload. </del> <ins> messages, each including a status code (status.codes).  The response might also contain header fields for server information, resource metadata, and representation metadata (header.and.trailer.fields), a payload body (payload.body) to be interpreted in accordance with the status code, and trailer fields for metadata collected while sending the payload. </ins> <del> One of the functions of the message framing mechanism is to assure that messages are </del> <ins> One of the functions of message framing is to assure that messages are </ins> . A message is considered complete when all of the octets indicated by its framing are available.  Note that, when no explicit framing is

Related discussion:
text: Does this mean it's now valid to interleave HTTP/2 DATA frames and HEADER frames?
Does this mean we cannot implement this on HTTP/2?
The feature was removed during WGLC, but no -- it would have required a new frame type.
Okay, so chunk extensions remains a unique feature of HTTP/1 chunked encoding and there is no plan to expand that further?
Yes.
As discussed in and URL, mid-stream trailers (i.e., those that arrive before the end of the payload body) are interesting. A few things to discuss: [ ] What are some potential use cases?[ ] We recently stopped automatically combining trailers into headers, as that created a lot of issues. What about these -- are they yet again distinct from trailers as well as headers? Or can they be "downgraded" into trailers automatically? In other words, when transitioning from a hop that supports these from one that doesn't, are they just dropped onto the floor?[ ] Related - is the expectation that implementations will create separate APIs for these, or would it be that trailers are just available / writable early?[ ] What relationship does one of these have to the payload body? E.g., could I write one that "knows" exactly where in the body it occurs, so that it could sign a chunk of the body relative to it? Or could a handling implementation change its ordering in relation to body bytes?
Some preliminary considerations. Incremental checksums eg. Service management (eg. convey the ETA of the transfer, ...) Sending signatures of partial body (in mid-stream) has some complexities respect to sending a signature of the whole message in the header/trailer section, and requires a security URL trailers, when used for integrity can't be dropped without informing the user agent They probably need to be defined as 1#field-item because mid-stream trailers will be sent multiple times (eg. one per chunk) Whenever they are tied to the partial transmitted representation, they will eventually be unuseful when merged, unless they have some associative propertyThey will be especially useful when tied to a portion of the body They will be significantly less useful when not tied to a portion of the body
Potential use cases mostly limited to long-lived streaming traffic, i.e.