void register_writer_node(struct writer_node *wn, struct btr_node *parent);
int setup_writer_node(const char *arg, struct btr_node *parent,
struct writer_node *wn);
void register_writer_node(struct writer_node *wn, struct btr_node *parent);
int setup_writer_node(const char *arg, struct btr_node *parent,
struct writer_node *wn);