silc_task_del_by_callback(schedule->timeout_queue, callback);
silc_task_del_by_callback(schedule->fd_queue, callback);
silc_task_del_by_callback(schedule->generic_queue, callback);
silc_task_del_by_callback(schedule->timeout_queue, callback);
silc_task_del_by_callback(schedule->fd_queue, callback);
silc_task_del_by_callback(schedule->generic_queue, callback);