code: @Deprecated
      @Override
      public StringBuffer format(final long millis, final StringBuffer buf) {
          return printer.format(millis, buf);
      }
docs: <p>Formats a millisecond {@code long} value into the
  supplied {@code StringBuffer}.</p>
  
  @param millis  the millisecond value to format
  @param buf  the buffer to format into
  @return the specified string buffer
  @since 2.1
  @deprecated Use {{@link #format(long, Appendable)}.