private void handle403(RoutingContext context, String error, String message) {
                String value = MessageFormat.format("Basic realm=\"{0}\" error=\"{1}\" error_message=\"{2}\"", "apiman-gw", error, message);
                context.response().putHeader("WWW-Authenticate", value);
                context.fail(403);
            }
@author Marc Savy {@literal <marc@rhymewithgravy.com>}
gateway/platforms/vertx3/vertx3/src/main/java/io/apiman/gateway/platforms/vertx3/api/auth/KeycloakOAuthFactory.java