code: public static void show(Date startDefault, Date endDefault, IResponseCallback<DateRange> callback) {
          show(new DateRange(startDefault, endDefault), callback);
      }
docs: Displays the date range dialog.
  
  @param startDefault Default start date.
  @param endDefault Default end date.
  @param callback Callback for returning a date range reflecting the inputs from the dialog.
  This will be null if the input is cancelled or if an unexpected error occurs.