title: SignalR IUserIdProvider not invoked for userid and connectionid mapping
body: <p>I am sending userid from javascript while i am making request to signalr as follows:</p>
  
  <pre><code> var userId = "1";
      var connection = $.hubConnection("/signalr", { useDefaultPath: false });
      var notificationsHubProxy = connection.createHubProxy('NotificationsHub');
      connection.qs = "userId=" + userId;
      notificationsHubProxy.on('notify', function (notifications) {
          notifyAll(notifications);
      });
      connection.start()
          .done(function() {
              notificationsHubProxy.invoke('getNotifications', "1,2,3");
          })
          .fail(function(reason) {
              alert('signalr error');
          });
  </code></pre>
  
  <p>Here is the class for implementing IUserIdProvider that retrieves querystring and returns as userId, i debugged and this class and GetUserId method was not invoked by the framework.</p>
  
  <pre><code> public class RealTimeNotificationsUserIdProvider : IUserIdProvider
  {
      public string GetUserId(IRequest request)
      {
        return  request.QueryString["userId"];
      }
  }
  </code></pre>
  
  <p>Here is my startup class for hooking up IUserId provider with signalR configuration:</p>
  
  <pre><code>      var userIdProvider = new RealTimeNotificationsUserIdProvider();
          GlobalHost.DependencyResolver.Register(typeof(IUserIdProvider), () =&gt; userIdProvider);
          app.Map("/signalr", map =&gt;
         {
             var hubConfiguration = new HubConfiguration
             {            
                  EnableDetailedErrors  = true,
                  Resolver = dependencyResolver,
                  EnableJavaScriptProxies = false
             };
             map.RunSignalR(hubConfiguration);
         });
  </code></pre>
  
  <p>Now, when i try to send notification to a particular User by accessing Clients.User(userId) its not working:</p>
  
  <pre><code>        var userId = "1";
          Clients.User(userId).notify("test");
  </code></pre>
  
  <p>what am i missing? Please help.</p>