Call specific client from SignalR

I want to call specific client from server, and not broadcast to all of them. Problem is that I’m in scope of some AJAX request (in .aspx codebehind let say), and not in Hub or PersistentConnection, so don’t have Clients property – and client who made that ajax (jquery) call is not the client I want to send signalr message!

SignalR – Checking if a user is still connected

I have a hub with method that is called client-side. This method launches a timer with a delegate that runs every 10 seconds. Since it wouldn’t make sense to keep running this delegate if no one is connected to the hub, I want to check if any users are still connected from inside the delegate before I reschedule it. Is there any way to do this?