Method insert

src/fl/stl/multi_map.h:316–320

Insert always succeeds for multimap

    // Insert always succeeds for multimap
    iterator insert(const value_type& value) {
        ValueWithId vwid(value, mNextId++);
        auto result = mTree.insert(vwid);
        return iterator(result.first);
    }

    iterator insert(value_type&& value) {
        ValueWithId vwid(fl::move(value), mNextId++);