code: func (a *TCPAcceptor) ListenAndServe() {
  	if a.hasTLSCertificates() {
  		a.ListenAndServeTLS(a.certFile, a.keyFile)
  		return
  	}
  
  	listener, err := net.Listen("tcp", a.addr)
  	if err != nil {
  		logger.Log.Fatalf("Failed to listen: %s", err.Error())
  	}
  	a.listener = listener
  	a.running = true
  	a.serve()
  }
docs: // ListenAndServe using tcp acceptor