public String toString(JSONWriter.Feature... features) {
        try (JSONWriter writer = JSONWriter.of(features)) {
            writer.setRootObject(this);
            writer.write(this);
            return writer.toString();
        }
    }
Serialize to JSON {@link String}

@param features features to be enabled in serialization
@return JSON {@link String}
core/src/main/java/com/alibaba/fastjson2/JSONObject.java