func setupRootZone() {
dns.HandleFunc(".", func(w dns.ResponseWriter, r *dns.Msg) {
m := new(dns.Msg)
m.SetRcode(r, dns.RcodeRefused)
w.WriteMsg(m)
})
}
func addHandler(zones Zones, name string, config *Zone) {
oldZone := zones[name]
config.SetupMetrics(oldZone)
zones[name] = config
dns.HandleFunc(name, setupServerFunc(config))
}