default Optional<Integer> getClientDestinationPort() {
        throw new UnsupportedOperationException();
    }
Reflects the actual destination port that the client intended to communicate with,
in preference to the port Zuul was listening on. In the case where proxy protocol is
enabled, this should reflect the destination IP encoded in the TCP payload by the load balancer.
zuul-core/src/main/java/com/netflix/zuul/message/http/HttpRequestInfo.java