private static void warnIfServiceHasMultipleRoutes(String path, HttpService service) {
        if (service instanceof ServiceWithRoutes) {
            if (!Flags.reportMaskedRoutes()) {
                return;
            }

            if (((ServiceWithRoutes) service).routes().size() > 0) {
                logger.warn("The service has self-defined routes but the routes will be ignored. " +
                            "It will be served at the route you specified: path={}, service={}. " +
                            "If this is intended behavior, you can disable this log message by specifying " +
                            "the -Dcom.linecorp.armeria.reportMaskedRoutes=false JVM option.",
                            path, service);
            }
        }
    }
Returns a list of {@link ServerPort}s which consists of distinct port numbers except for the port
{@code 0}. If there are the same port numbers with different {@link SessionProtocol}s,
their {@link SessionProtocol}s will be merged into a single {@link ServerPort} instance.
The returned list is sorted as the same order of the specified {@code ports}.
core/src/main/java/com/linecorp/armeria/server/ServerBuilder.java