code: function updateEntryRequest(entry) {
      var xw = createXMLWriter(true);
  
      Object.keys(entry)
          .filter(function(key) {
              // filter out internal properties
              return key.indexOf('_') !== 0;
          })
          .forEach(function(key) {
              xw = xw.startElement('gsx:' + key)
                  .text(util.coerceNumber(entry[key]).toString())
                  .endElement();
          });
  
      return xw.endElement().toString();
  }
docs: Creates an 'update entry' request payload
  
  @param entry
  @returns {*}