Reliable Stream Resets: Requesting a Reset at a Specific Offset

[Marten Seemann <[e-mail]>]

The Reliable Reset draft introduces a CLOSE_STREAM frame that allows
resetting a stream at a specific offset, thereby guaranteeing the reliable
delivery of stream data up that offset.

At IETF 117, there was some discussion (mainly in AVT) about whether there
should be a method for an endpoint to abort reading at a specific offset.
This would allow an endpoint to communicate that it's only interested in
the first N bytes of the stream, and that it will discard all bytes beyond
N. This could be done by introducing a STOP_SENDING frame that carries an
extra field to carry the value N.

This might be useful if the stream is used to send a sequence of
(TLV-encoded) media frames, and the receiver knows the size of the frame
before actually receiving the entirety of it, or in cases where the
receiver possesses out-of-band knowledge about the frame size.

I created a PR to make this proposal more specific:
https://github.com/quicwg/reliable-stream-reset/pull/26. This PR is based
on Martin Thomson's ENOUGH draft (
https://datatracker.ietf.org/doc/draft-thomson-quic-enough/).

Is this mechanism actually useful enough to be included in the draft?
Implementing support for this frame seems quite easy, but it would be
helpful to learn more about use cases it enables first.