C++ mt19937 always giving same number, even when seeding

I am currently having an issue where my RNG is always giving me the same number - even when I am (supposedly) seeding the value every time.

the code in the class is:

    int RandomNumberGenerator()
{
    std::mt19937 engine;
    auto seed = std::chrono::high_resolution_clock::now().time_since_epoch().count();
    engine.seed((unsigned long)seed);
    std::uniform_int_distribution<int> distribution(0, 100);

    return distribution(engine);
}

And the code calling it is:

vector<int> iv;
    generate_n(back_inserter(iv), 5, RandomNumberGenerator);
    cout << "\nVector content: ";
    copy(iv.begin(), iv.end(), ostream_iterator<int>(cout, " "));

Surely each time the generate_n function