code: func (c Chaos) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
  	state := request.Request{W: w, Req: r}
  	if state.QClass() != dns.ClassCHAOS || state.QType() != dns.TypeTXT {
  		return plugin.NextOrFailure(c.Name(), c.Next, ctx, w, r)
  	}
  
  	m := new(dns.Msg)
  	m.SetReply(r)
  
  	hdr := dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeTXT, Class: dns.ClassCHAOS, Ttl: 0}
  	switch state.Name() {
  	default:
  		return c.Next.ServeDNS(ctx, w, r)
  	case "authors.bind.":
  		for a := range c.Authors {
  			m.Answer = append(m.Answer, &dns.TXT{Hdr: hdr, Txt: []string{trim(a)}})
  		}
  	case "version.bind.", "version.server.":
  		m.Answer = []dns.RR{&dns.TXT{Hdr: hdr, Txt: []string{trim(c.Version)}}}
  	case "hostname.bind.", "id.server.":
  		hostname, err := os.Hostname()
  		if err != nil {
  			hostname = "localhost"
  		}
  		m.Answer = []dns.RR{&dns.TXT{Hdr: hdr, Txt: []string{trim(hostname)}}}
  	}
  	state.SizeAndDo(m)
  	w.WriteMsg(m)
  	return 0, nil
  }
docs: // ServeDNS implements the plugin.Handler interface.