func (s *srv) start() error {
	log.Infof("%s start", s)
	switch s.state {
	case srvStateInit:
		listener, err := net.Listen(s.listener.Address.Network, s.listener.Address.Address)
		if err != nil {
			return err
		}

		if s.isTLS() {
			config, err := s.newTLSConfig()
			if err != nil {
				return err
			}
			listener = manners.NewTLSListener(
				manners.TCPKeepAliveListener{listener.(*net.TCPListener)}, config)
		}
		s.srv = manners.NewWithOptions(
			manners.Options{
				Server:       s.newHTTPServer(),
				Listener:     listener,
				StateHandler: s.mux.connTracker.onStateChange,
			})
		s.state = srvStateActive
		go s.serve(s.srv)
		return nil
	case srvStateHijacked:
		s.state = srvStateActive
		go s.serve(s.srv)
		return nil
	}
	return fmt.Errorf("%v Calling start in unsupported state", s)
}
func (s *srv) takeFile(f *FileDescriptor) error {
	log.Infof("%s takeFile %v", s, f)

	listener, err := f.ToListener()
	if err != nil {
		return err
	}

	if s.isTLS() {
		tcpListener, ok := listener.(*net.TCPListener)
		if !ok {
			return fmt.Errorf(`%s failed to take file descriptor - it is running in TLS mode so I need a TCP listener, 
but the file descriptor that was given corresponded to a listener of type %T. More about file descriptor: %s`, listener, s, f)
		}
		config, err := s.newTLSConfig()
		if err != nil {
			return err
		}
		listener = manners.NewTLSListener(
			manners.TCPKeepAliveListener{tcpListener}, config)
	}

	s.srv = manners.NewWithOptions(
		manners.Options{
			Server:       s.newHTTPServer(),
			Listener:     listener,
			StateHandler: s.mux.connTracker.onStateChange,
		})
	s.state = srvStateHijacked
	return nil
}