code: public void setDate(String headerName, long date) {
  		SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMATS[0], Locale.US);
  		dateFormat.setTimeZone(GMT);
  		set(headerName, dateFormat.format(new Date(date)));
  	}
docs: Set the given date under the given header name after formatting it as a string
  using the pattern {@code "EEE, dd MMM yyyy HH:mm:ss zzz"}. The equivalent of
  {@link #set(String, String)} but for date headers.