Method triggerEvent

/**
 * Calls all handlers associated with an event group.
 *
 * This is a legacy method, implementing old-style (Joomla! 3.x) plugin calls. It's best to go directly through the
 * Dispatcher and handle the returned EventInterface object instead of going through this method. This method is
 * deprecated and will be removed in Joomla! 5.x.
 *
 * This method will only return the 'result' argument of the event
 *
 * @param   string       $eventName  The event name.
 * @param   array|Event  $args       An array of arguments or an Event object (optional).
 *
 * @return  array  An array of results from each function call. Note this will be an empty array if no dispatcher is set.
 *
 * @since       4.0.0
 * @throws      \InvalidArgumentException
 * @deprecated  5.0
 */
public function triggerEvent($eventName, $args = []);