protected Map<String, String> toFlatStringMap(JsonObject jsonObject) {
        if (jsonObject == null)
            return Collections.emptyMap();

        Map<String, String> outMap = new LinkedHashMap<>();
        jsonMapToProperties("", new JsonObject(jsonObject.encode()), outMap);
        return outMap;
    }
@see io.apiman.gateway.engine.IEngineConfig#getGatewayInitializers(io.apiman.gateway.engine.IPluginRegistry)
gateway/platforms/vertx3/vertx3/src/main/java/io/apiman/gateway/platforms/vertx3/common/config/VertxEngineConfig.java