code: func (e *ECU) monitoring() {
  	ln, err := net.Listen("tcp", e.cfg.MonitorAddress)
  	if err != nil {
  		log.Fatal("listen error:", err)
  	}
  
  	monitorHTTP := &http.Server{
  		ReadTimeout:    30 * time.Second,
  		WriteTimeout:   30 * time.Second,
  		MaxHeaderBytes: 1 << 20,
  	}
  	go monitorHTTP.Serve(ln)
  
  	<-e.shutdownMonitor
  	ln.Close()
  	e.shutdownMonitor <- true
  }
docs: // monitoring starts an HTTP server for monitoring purposes.