(PECL libevent >= 0.0.2)
event_timer_set — Prepare a timer event
   Prepares the timer event to be used in event_add(). The
   event is prepared to call the function specified by the
   callback when the event timeout elapses.
  
After initializing the event, use event_base_set() to associate the event with its event base.
   In case of matching event, these three arguments are passed to the
   callback function:
   
fdSignal number or resource indicating the stream.
events
       A flag indicating the event. This will always be
       EV_TIMEOUT for timer events.
      
arg
       Optional parameter, previously passed to
       event_timer_set() as arg.
      
eventValid event resource.
callbackCallback function to be called when the matching event occurs.
argOptional callback parameter.
   Returns TRUE on success or FALSE on failure.