code: func NewDNSChecker(ip net.IP, port int) *DNSChecker {
  	return &DNSChecker{
  		Target: Target{
  			IP:    ip,
  			Port:  port,
  			Proto: seesaw.IPProtoUDP,
  		},
  		Question: dns.Question{
  			Qclass: dns.ClassINET,
  			Qtype:  dns.TypeA,
  		},
  	}
  }
docs: // NewDNSChecker returns an initialised DNSChecker.