Method upper_bound

src/fl/stl/multi_set.h:337–340

    }

    iterator upper_bound(const Key& key) {
        ValueWithId search_key(key, mNextId);  // Use mNextId to get upper bound
        return iterator(mTree.upper_bound(search_key));
    }

    const_iterator upper_bound(const Key& key) const {
        ValueWithId search_key(key, mNextId);