code: func NewV4(pubkey *ecdsa.PublicKey, ip net.IP, tcp, udp int) *Node {
  	var r enr.Record
  	if ip != nil {
  		r.Set(enr.IP(ip))
  	}
  	if udp != 0 {
  		r.Set(enr.UDP(udp))
  	}
  	if tcp != 0 {
  		r.Set(enr.TCP(tcp))
  	}
  	signV4Compat(&r, pubkey)
  	n, err := New(v4CompatID{}, &r)
  	if err != nil {
  		panic(err)
  	}
  	return n
  }
docs: // NewV4 creates a node from discovery v4 node information. The record
  // contained in the node has a zero-length signature.