def to_s(indent = xml_tab_width)
      xml = ''
      if defined? Ox
        ox_doc = Ox.parse(xml_response)
        xml = Ox.dump(ox_doc, indent: indent)
      else
        rexml_doc = REXML::Document.new(xml_response)
        rexml_doc.write(xml, indent)
      end
      xml
    end
def to_s(indent = xml_tab_width)
      xml = ''
      if defined? Ox
        ox_doc = Ox.parse(xml_response)
        xml = Ox.dump(ox_doc, indent: indent)
      else
        rexml_doc = REXML::Document.new(xml_response)
        rexml_doc.write(xml, indent)
      end
      xml
    end
Get a String representation of the response XML with indentation.
 @return [String] the response XML.