in src/annoyluamodule.cc [223:231]
static int get_item_vector(lua_State* L) {
Impl* self = getAnnoy(L, 1);
int item = getItemIndex(L, 2, self->get_n_items());
std::vector<AnnoyT> _vec(self->get_f());
AnnoyT* vec = &(_vec[0]);
self->get_item(item, vec);
pushVector(L, _vec);
return 1;
}