Prioritizing QUIC streams?

is it possible to assign different priorities to the streams?

No.

If you’re using HTTP/3 and talking to a server that supports it, you can set headers to request that the server prioritise streams. However, there’s no facility for setting a priority at the QUIC layer within Network framework.

If you’d like to see such support added in the future, I encourage you to file an enhancement request describing your requirements.

Please post your bug number, just for the record.

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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Thank you for the answer, Quinn, I appreciate it!

Would NWConnection.ContentContext.relativePriority work to prioritize messages relative to each other? That is, would they get re-ordered based on their assigned priorities? Presumably only as long as multiple messages are queued in the on-device send buffer?

And if this does work, I assume it would only work within a single NWConnection? Or would messages from multiple NWConnections sharing a single QUIC tunnel also get re-ordered based on their relative priorities?

My context is that I am working on a (relatively) simple custom video streaming protocol built on top of QUIC, trying to use some ideas from the "Media over QUIC" project. One of those is using a QUIC stream per frame so that I can cancel transmission of old queued frames if there is congestion, while also prioritizing some frames (I-frames) over others.

My understanding is that this lack of prioritisation is inherent to the QUIC protocol implementation, thus this API won’t help.

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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

Thank you. That's unfortunate. I'll file an enhancement request as you suggested.

I just filed the enhancement request as FB15642049