pub fn new_uninit_in(alloc: A) -> Box<mem::MaybeUninit<T>, A> {
        let layout = Layout::new::<mem::MaybeUninit<T>>();
        // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
        // That would make code size bigger.
        match Box::try_new_uninit_in(alloc) {
            Ok(m) => m,
            Err(_) => handle_alloc_error(layout),
        }
    }
Constructs a new `Box` with uninitialized contents, with the memory
being filled with `0` bytes in the provided allocator,
returning an error if the allocation fails,

See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
of this m
benchmarks/haystacks/code/rust-library.rs