QMultiMap::upperBound() const iterator issue

using TestMultiMap = QMultiMap<int, QByteArray>;

void test(TestMultiMap m)
{
    for (auto it = m.cbegin(), end = m.cend(); it != end; ) {
        const auto &key = it.key();
        TestMultiMap::const_iterator keyEnd = m.upperBound(key);
        const auto count = std::distance(it, keyEnd);
        qDebug() << it.key() << "count=" << count;
        for ( ; it != keyEnd; ++it)
            qDebug() << it.key() << it.value();
    }
}