# File lib/time.rb, line 422
  def httpdate
    t = dup.utc
    sprintf('%s, %02d %s %d %02d:%02d:%02d GMT',
      RFC2822_DAY_NAME[t.wday],
      t.day, RFC2822_MONTH_NAME[t.mon-1], t.year,
      t.hour, t.min, t.sec)
  end