How to expose raw memory without numpy

[yobeonline]

I have a situation similar to what is described in #2271. In short, I expose a C++ object that has a std:vector<std::vector<T>> columns attribute. A member function taking an index returns the selected nested vector as a numpy array:

auto get_array(size_t i) const {
  return py::array_t<T>{columns[i].size(), columns[i], py::cast(*this)};
}

Out of curiosity, I am trying to do it without the numpy dependency. I believe it means my get_array function should now return a py::memoryview instance:

auto get_memview(size_t i) const {
  return py::memoryview::frum_buffer(
    columns[i].datat(),
    sizeof(T),
    py::format_descriptor<T>::format(),
    {data[i].size()},
    {sizeof(T)},
    true,
  );
}

My problem is that I can't find how to pass the py::cast(*this) reference to tie the lifetime of this and the memoryview object. I have reached the point where I doubt memoryviews were design to do what I am trying to do and am wondering what I should use instead or if it is even possible to not use numpy arrays.