code: public StringBuffer format(Date date, StringBuffer buf) {
          Calendar c = new GregorianCalendar(mTimeZone);
          c.setTime(date);
          return applyRules(c, buf);
      }
docs: <p>Formats a <code>Date</code> object into the
  supplied <code>StringBuffer</code>.</p>
  
  @param date  the date to format
  @param buf  the buffer to format into
  @return the specified string buffer