Add support to SignalR for Session

[danroth27]

[analogrelay]

What's the context here? SignalR doesn't really have a way of clearly tracking the Session since it involves multiple requests, this is why Context.Items exists, for storing per-Connection metadata.

[danroth27]

@davidfowl In server-side Blazor projects we run Blazor on the server and then use SignalR to send UI updates to the browser and to send event notifications back to the server. We'd like to have a way for app developers to maintain state across connections.

[analogrelay]

Is Context.Items not sufficient for this? That's a dictionary that is maintained across the entire life of the connection. Or do you need direct access to the existing Session data?

maintain state across connections

Across multiple connections by the same user?

[danroth27]

Yes, we'd like a way to maintain state across connections for the same user.

[analogrelay]

We've had some discussions about this, but all of them require fairly significant work we don't have resources for in 2.2, so I'm putting this in 3.0 for now.