Update http3 RequiresPreviewFeatures attributes with message/URL

[adityamandaleeka]

Fixes #36450

Keeping in draft while we confirm this actually works "for real" in VS. It doesn't work yet with the current SDK.

[adityamandaleeka]

@pgovind Is this feature ready for use?

[pgovind]

Is this feature ready for use?

.NET 6 is not going to support showing a message/URL in the analyzer diagnostic. All diagnostic currently point to aka.ms/dotnet-warnings/preview-features. We just didn't have enough time to bake that into RC2. The analyzer itself will be turned on with a severity of Error by default in RC2 though. As a workaround, we could consider adding some blurbs specific to Http3 at aka.ms/dotnet-warnings/preview-features when it comes online?

cc @jeffhandley

[adityamandaleeka]

Thanks @pgovind. So if we were to merge this now, the feature would light up at some point in the future?

I don't have a strong preference on whether we need to include http3-specific messaging on the general "what are preview features" link, though it may be interesting to have a page for each release going forward that has a list of features that are considered preview in that release, and to point to that from the general preview features link.

[adityamandaleeka]

@pgovind Can you confirm if this is correct:

So if we were to merge this now, the feature would light up at some point in the future?

[pgovind]

So if we were to merge this now, the feature would light up at some point in the future?

Apologies, I missed the notification for the previous comment. Indeed, this will light up in the future as soon as dotnet/roslyn-analyzers#5502 is merged and the bits flow everywhere.