docs: void xmlWriteOn(FormattedWriter writer) throws IOException 
      {
          writer.newLine();
          writer.startTag(XML_UNSTORED_ITEM_MANAGER);
          writer.indent();
          _list.xmlWriteOn(writer);
          writer.outdent();
          writer.newLine();
          writer.endTag(XML_UNSTORED_ITEM_MANAGER);
      }