* task = g_task_new (self, cancellable, callback, user_data);
* g_task_set_task_data (task, cake_data, (GDestroyNotify) cake_data_free);
* g_task_run_in_thread (task, bake_cake_thread);
* task = g_task_new (self, cancellable, callback, user_data);
* g_task_set_task_data (task, cake_data, (GDestroyNotify) cake_data_free);
* g_task_run_in_thread (task, bake_cake_thread);