code: func Start(config *config.Config, handler http.Handler) {
  	mu.Lock()
  	defer mu.Unlock()
  
  	cfg = config
  	port := config.Choria.StatsPort
  
  	if port == 0 {
  		log.Infof("Statistics gathering disabled, set plugin.choria.stats_port")
  		return
  	}
  
  	prometheus.MustRegister(buildInfo)
  	buildInfo.WithLabelValues(build.Version, build.SHA).Inc()
  
  	if !running {
  		log.Infof("Starting statistic reporting Prometheus statistics on http://%s:%d/choria/", config.Choria.StatsListenAddress, port)
  
  		if handler == nil {
  			http.HandleFunc("/choria/", handleRoot)
  			http.Handle("/choria/prometheus", promhttp.Handler())
  
  			go http.ListenAndServe(fmt.Sprintf("%s:%d", config.Choria.StatsListenAddress, port), nil)
  		} else {
  			hh := handler.(*http.ServeMux)
  			hh.HandleFunc("/choria/", handleRoot)
  			hh.Handle("/choria/prometheus", promhttp.Handler())
  		}
  
  		running = true
  	}
  }
docs: // Start starts serving exp stats and metrics on the configured statistics port