Function slice_as_chunks_unchecked_mut 

unsafe fn slice_as_chunks_unchecked_mut<T, const N: usize>(
    slice: &mut [T],
) -> &mut [[T; N]]

Rust core [T]::as_chunks_unchecked_mut vendored because of its 1.88 MSRV. TODO(tarcieri): use upstream function when we bump MSRV