protected boolean shouldRenderUtf8Value(String name, int length) {
            if (settings.debugRendering) return true;
            if (name.startsWith(VESPA_HIDDEN_FIELD_PREFIX)) return false;
            if (length == 0) return false;
            return true;
        }
Call after all fields in a hit to close the "fields" field of the JSON object
container-search/src/main/java/com/yahoo/search/rendering/JsonRenderer.java