///

/// You can think of this like `.get(index).unwrap_unchecked()`. It's UB

/// to call `.get_unchecked(len)`, even if you immediately convert to a

/// pointer. And it's UB to call `.get_unchecked(..len +1)`,

/// pointer. And it's UB to call `.get_unchecked(..len + 1)`,

/// `.get_unchecked(..=len)`, or similar.

///

/// [`get`]: slice::get

///

/// You can think of this like `.get_mut(index).unwrap_unchecked()`. It's

/// UB to call `.get_unchecked_mut(len)`, even if you immediately convert

/// to a pointer. And it's UB to call `.get_unchecked_mut(..len +1)`,

/// to a pointer. And it's UB to call `.get_unchecked_mut(..len + 1)`,

/// `.get_unchecked_mut(..=len)`, or similar.

///

/// [`get_mut`]: slice::get_mut