Add a public HttpConnection.ConnectionId

[KPixel]

Would it be ok to make the ConnectionId visible outside of HttpConnection?
Something like:

public string ConnectionId => _connectionId;

It could also be exposed through the Features property if you don't want to expose it directly like that.

Reason: When using the Sockets library, the client has no way of knowing its own ConnectionId.
I am working on a scenario where the client needs to send it to a notification service (think of it as a decentralized presence system).

[davidfowl]

No because the client will not always have the connection id. See #788 (comment) (and generally the overall thread about this)

Also #932

[KPixel]

My bad. I didn't expect this issue to have already been discussed, so I didn't search for it.

I am going to continue this discussion here: #961.