More integration for Blazor Server and SignalR

[SteveSandersonMS]

@DamianEdwards:

Today in the typical case one ends up with multiple connections from the client to the server: one for the Blazor circuit, the other for the app’s SignalR hubs

I expect the key scenario here would be scaling out notifications across multiple servers via SignalR's backplane support (because otherwise, Blazor Server already inherently has notification/update support within a single server).

[TanayParikh]

Added to consolidated #38127. fyi/ @javiercn

[DamianEdwards]

@SteveSandersonMS it's also about the programming model. SignalR's Hub primitives include one-to-one and one-to-many RPC from server to client, including support for arbitrary grouping of clients, and yes these concepts then scale seamlessly to scaled-out deployments. Building a multi-user chat app in "pure" Blazor Server today is totally possible, but would require the app to manage some of the aspects inherent in such a scenario manually (e.g. there's no concept of invoking a method on multiple circuits).

Adding @bradygaster and @davidfowl for their thoughts.

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
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[mkArtakMSFT]

We haven't seen real-life scenarios where this is actually necessary. So closing for now.