EXTEND(SP, 4 at t/21-iter.t line 167.
Accessing ST(0), ST(1) at t/21-iter.t line 167.
Accessing ST(2), ST(3) at t/21-iter.t line 167.
XSRETURN(4) at t/21-iter.t line 167.
not ok 6 - iter_get_multi {
    ok 1 - next_keys(*)
    ok 2 - next_keys overshoot
    ok 3 - reverse next_keys overshoot
    ok 4 - reverse next_keys for 1
    ok 5 - iterate nothing
    ok 6 - next_values(4)
    ok 7 - next_nodes(2)
}
# Failed test 'iter_get_multi'
# at t/21-iter.t line 172.
# Caught exception in subtest: panic: XSUB Tree::RB::XS::Iter::next_kv (TreeRBXS.c) failed to extend arg stack: base=56076974fa88, sp=56076974faa8, hwm=56076974faa0