public static function bind($event, $callback, $priority = Event::PRIORITY_NORMAL) {
        $event = strtolower($event);
        self::$handlers[$event][$priority][] = $callback;
        self::$toSort[$event] = true;
    }
public static function bind($event, $callback, $priority = Event::PRIORITY_NORMAL) {
        $event = strtolower($event);
        self::$handlers[$event][$priority][] = $callback;
        self::$toSort[$event] = true;
    }
public static function bind ( $ event , $ callback , $ priority = Event :: PRIORITY_NORMAL ) { $ event = strtolower ( $ event ) ; self :: $ handlers [ $ event ] [ $ priority ] [ ] = $ callback ; self :: $ toSort [ $ event ] = true ; }
Bind an event handler to an event.

@param string $event The naame of the event to bind to.
@param callback $callback The callback of the event.
@param int $priority The priority of the event.
Bind an event handler to an event .