public int getFunctionalTcpPort() {
    return tcpPort.orElse(udpPort);
  }
If the tcp port is explicitly defined, return it. Otherwise, return the udp port assuming that
the tcp port should match the udp port.

@return The tcp port to use for this endpoint.
ethereum/p2p/src/main/java/org/hyperledger/besu/ethereum/p2p/discovery/Endpoint.java