docs: public static String getDateString(Date date) {
          SimpleDateFormat sdf = new SimpleDateFormat(sdformatMillisec);
          sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
          StringBuffer dateBuffer = new StringBuffer(sdf.format(date));
          // above string is in this format
          //    2005-05-04T09:34:18.444-0400
          // convert it to
          //    2005-05-04T09:34:18.444-04:00
          dateBuffer.insert(dateBuffer.length() - 2, ":");
          return dateBuffer.toString();
      }