Original alarm and delay methods:

...
         # Post an event which will be delivered after a delay, specified in
         # seconds hence. This clears previous timed events with the same
         # name.
         $kernel->delay( $event, $seconds, @event_args );

         # Post an additional delay, leaving existing ones in the queue.
         $kernel->delay_add( $event, $seconds, @event_args );

       June 2001 alarm and delay methods:

...
         # Post an event which will be delivered a number of seconds hence.
         # This does not clear previous events with the same name.
         $alarm_id = $kernel->delay_set( $event, $seconds_hence, @etc );
...
         # Refresh an existing delay to a number of seconds in the future.
         $kernel->delay_adjust( $delay_id, $number_of_seconds_hence );

...