* Insert a new item into the queue, which should be put in the right place according to its priority. 	 * That is, is order == ASC, then the new item should appear in the queue before all items with a 	 * HIGHER priority. If order == DESC, then the new item should appear in the queue before all items 	 * with a LOWER priority. 	 * @param data 	 * @param priority 	 */