No, the cat’s out of the bag with span (and unique pointer) now, we can’t go back. We knew this was a problem from unique_ptr and had an opportunity to not make

No, the cat’s out of the bag with span (and unique pointer) now, we can’t go back. We knew this was a problem from unique_ptr and had an opportunity to not make the same mistake again, but instead we chose back compat for a new feature over something novel and performant