It seemed like we're doomed...
Yet we barely escaped our horrid fate, because the C++ structured bindings happen to look also for get<i> member functions!
Any other solution involving a free function `get<i>(h)` would not work, since the `std::tuple` used as base class would inevitably drag in std::get via ADL
Obviously, the other remedy would be to turn the `StorageFrame` into a member; yet doing so is not desirable, as makes the actual storage layout more obscure (and also more brittle)