The one in std uses unsafe. My main concern with learning rust is that you can spend ages trying to learn “the right way” of doing things in rust, when the right way really is to use unsafe.
No, the right way is to use unsafe primitives that have been tested, audited or even formally proven (like the ones in std).
Sometimes such a primitive doesn't exist and you should use unsafe yourself, but then you're the one supposed to make sure that your code is in fact sound. If you keep unsafe for small portions of the code you can reason about and extensively test so Miri gives you a good level of confidence, then it's fine to use unsafe. But it's the more expensive option, not the default.
