void btr_consume(struct btr_node *btrn, size_t numbytes);
int btr_exec_up(struct btr_node *btrn, const char *command, char **value_result);
void btr_splice_out_node(struct btr_node *btrn);
void btr_pushdown(struct btr_node *btrn);
void *btr_context(struct btr_node *btrn);
void btr_merge(struct btr_node *btrn, size_t dest_size);
void btr_consume(struct btr_node *btrn, size_t numbytes);
int btr_exec_up(struct btr_node *btrn, const char *command, char **value_result);
void btr_splice_out_node(struct btr_node *btrn);
void btr_pushdown(struct btr_node *btrn);
void *btr_context(struct btr_node *btrn);
void btr_merge(struct btr_node *btrn, size_t dest_size);