code: func NewResolver(address string, proxyDNS bool, resolverKey string, backend DNSBackend) Resolver {
  	return &resolver{
  		backend:       backend,
  		proxyDNS:      proxyDNS,
  		listenAddress: address,
  		resolverKey:   resolverKey,
  		err:           fmt.Errorf("setup not done yet"),
  		startCh:       make(chan struct{}, 1),
  	}
  }
docs: // NewResolver creates a new instance of the Resolver