code: func (s *Server) sessionStats() {
  	for {
  		select {
  		case <-time.After(5 * time.Second):
  			metrics.SetGauge([]string{"session_ttl", "active"}, float32(s.sessionTimers.Len()))
  
  		case <-s.shutdownCh:
  			return
  		}
  	}
  }
docs: // sessionStats is a long running routine used to capture
  // the number of active sessions being tracked