code: func (ln *LocalNode) UDPContact(toaddr *net.UDPAddr) {
  	ln.mu.Lock()
  	defer ln.mu.Unlock()
  
  	ln.udpTrack.AddContact(toaddr.String())
  	ln.updateEndpoints()
  }
docs: // UDPContact should be called whenever the local node has announced itself to another node
  // via UDP. It feeds the local endpoint predictor.