code: public GsonXml create() {
      if (coreBuilder == null) {
        coreBuilder = new GsonBuilder();
      }
      return new GsonXml(coreBuilder.create(), xmlParserCreator, options);
    }
docs: Creates a {@link GsonXml} instance based on the current configuration. This method is free of
  side-effects to this {@code GsonXmlBuilder} instance and hence can be called multiple times.
  
  @return an instance of GsonXml configured with the options currently set in this builder