[tialaramex]

The code size cost doesn't live in my code, but in yours.

Because I didn't admit you were getting a Vec, if you actually need a Vec you actually can't just use the one I gave you. You must jump though hoops to turn whatever I gave you into a Vec, bloating your code.

The implementation is pretty clever, it is probably not going to meticulously take my Vec to pieces, throw it away and make you a new one, instead just giving the same Vec. But this trick is fragile, so much better not to even need it.