(defun format-date (stream universal-time colon-modifier-p at-sign-modifier-p)
  (declare (ignore colon-modifier-p at-sign-modifier-p))
  (multiple-value-bind (seconds minutes hours day month year) (decode-universal-time universal-time)
    (format stream "~4,'0D-~2,'0D-~2,'0D ~2,'0D:~2,'0D:~2,'0D" year month day hours minutes seconds)))

(defun format-duration (stream seconds colon-modifier-p at-sign-modifier-p)
  (declare (ignore colon-modifier-p at-sign-modifier-p))
  (let ((seconds (mod (truncate seconds) 60))
        (minutes (mod (truncate seconds 60) 60))
        (hours (truncate seconds 3600))
        (milliseconds (truncate (mod (* seconds 1000) 1000))))
    (format stream "~2,'0D:~2,'0D:~2,'0D.~3,'0D" hours minutes seconds milliseconds)))

(format stream "Start: ~/ir-snowball::format-date/,
end: ~/ir-snowball::format-date/,
duration  ~/ir-snowball::format-duration/."
  start-time (get-universal-time) (- (get-universal-time) start-time))