rbtree_alloc
enum rbtree_alloc alloc;
struct rbtree __arena *rb_create(enum rbtree_alloc alloc, enum rbtree_insert_mode insert);
int insert_many(enum rbtree_alloc alloc, enum rbtree_insert_mode insert)
static inline int remove_many(enum rbtree_alloc alloc,
struct rbtree __arena *rb_create(enum rbtree_alloc alloc,