code: public void addValue(Date date) {
          String dateString = XmppDateTime.formatXEP0082Date(date);
          addValue(dateString);
      }
docs: Adds the given Date as XEP-0082 formated string by invoking {@link #addValue(CharSequence)} after the date
  instance was formated.
  
  @param date the date instance to add as XEP-0082 formated string.
  @since 4.3.0