code: function handler(responseCode, data, ioArgs) {
                      that.xhr = ioArgs.xhr;
                      that.statusCode = that.xhr && !that.xhr.timedOut && that.xhr.status || 0;
                      if (that.canceled) {
                          logger.debug("Request [" + that.id + "] was canceled, not calling handler");
                      } else {
                          that.pending = false;
                          that.complete = true;
                          paramHandler(responseCode, data, ioArgs);
                      }
                  }
docs: wrap the handler callbacks in a cancel check