+GST_API
+void gst_task_set_enter_callback (GstTask *task,
+ GstTaskThreadFunc enter_func,
+ gpointer user_data,
+ GDestroyNotify notify);
+GST_API
+void gst_task_set_leave_callback (GstTask *task,
+ GstTaskThreadFunc leave_func,
+ gpointer user_data,
+ GDestroyNotify notify);
+GST_API