73     private static $_register = [];  variable in Hoa\\Event\\Event
102         if (!isset(self::$_register[$eventId][self::KEY_EVENT])) {
103             self::$_register[$eventId] = [
109         return self::$_register[$eventId][self::KEY_EVENT];
152         if (!isset(self::$_register[$eventId][self::KEY_EVENT])) {
153             self::$_register[$eventId][self::KEY_EVENT] = new self();
156         self::$_register[$eventId][self::KEY_SOURCE] = $source;
172             unset(self::$_register[$eventId]);
174             self::$_register[$eventId][self::KEY_SOURCE] = null;
258             array_key_exists($eventId, self::$_register) &&
259             self::$_register[$eventId][self::KEY_SOURCE] !== null;