btree_txn_put
int btree_txn_put(struct btree *bt, struct btree_txn *txn,
btree_txn_put(bt, NULL, key, data, flags)
rc = btree_txn_put(NULL, ns->indx_txn, &key, &val,
rc = btree_txn_put(NULL, ns->indx_txn, &key, &val, BT_NOOVERWRITE);
rc = btree_txn_put(NULL, ns->data_txn, &key, &val,