whole_func_string: function () {
          var headers = [];
          Ext.Object.each(this.responseHeaders, function (name, value) {
              headers.push(name + ': ' + value);
          });
          return headers.join('\x0d\x0a');
      }
func_code_string: function () {
          var headers = [];
          Ext.Object.each(this.responseHeaders, function (name, value) {
              headers.push(name + ': ' + value);
          });
          return headers.join('\x0d\x0a');
      }
func_documentation_string: As in XMLHttpRequest.