`IUserIdProvider` peer Hub, and [...]

### Is your feature request related to a problem? Please describe.
When app **not** use standard `Authentication/Authorization` and there multiple type of account, the user info is from different cookies, there will be a problem to use the same type of `IUserIdProvider` that across different Hub.

### Questions

I can not reset the connection's userId, and also can not filter all the connection by filter `Context.Items`, and also can not get userId from a group , how do I do the following. For example:
- A chat room , that use can from anonymous state to login state, (is this user must disconnect and reconnect with login cookie)
- how to seed particular message to partial users of room (room managers or VIPs)
- show room users