private void session_StateChanged(object sender, SessionListenerEventArgs e)
        {
            Log.Spew("session_StateChanged:\n\tfrom " + e.OldState + "\n\tto   " + e.NewState);

            var justConnected = e.NewState.Connected && !e.OldState.Connected;
            var justDisconnected = !e.NewState.Connected && e.OldState.Connected;

            if (justConnected)
                topicManager = new TopicManager(e.Session, directInputManager, car, refreshIntervalManager, metrics); 
            
            if (justDisconnected)
                topicManager = null; 
        }