private static String[] optionalVar(String[] arr, String[] defaultArr) {
        if (arr == null || arr.length==0) {
            return defaultArr;
        }
        return arr;
    }
Build {@link HttpClientOptions} using populated {@link TLSOptions}.

@author Marc Savy {@literal <msavy@redhat.com>}
gateway/platforms/vertx3/vertx3/src/main/java/io/apiman/gateway/platforms/vertx3/http/HttpClientOptionsFactory.java