(PECL libevent >= 0.0.5)
event_priority_set — Assign a priority to an event.
$event
   , int $priority
   )
   Assign a priority to the event.
  
eventValid event resource.
priorityPriority level. Cannot be less than zero and cannot exceed maximum priority level of the event base (see event_base_priority_init()).
   Returns TRUE on success or FALSE on failure.