btree_search_node
node = btree_search_node(bt, mp, key, &exact, &i);
leaf = btree_search_node(bt, mp, key, &exact, NULL);
leaf = btree_search_node(cursor->bt, mp, key, exactp, &top->ki);
static struct node *btree_search_node(struct btree *bt, struct mpage *mp,
leaf = btree_search_node(bt, mp, key, &exact, &ki);
leaf = btree_search_node(bt, mp, key, &exact, &ki);