static Optional<Integer> initUDP(final Map<String, Bytes> data) {
    var udpBytes = data.get("udp");
    return udpBytes != null ? Optional.of(udpBytes.toInt()) : initTCP(data);
  }
The UDP port of the ENR. If the UDP port is not present, the TCP port is used.

@return the UDP port associated with this ENR
ethereum/p2p/src/main/java/org/hyperledger/besu/ethereum/p2p/discovery/dns/EthereumNodeRecord.java