rust randombytes function that returns an array

randombytes.rs

/* Written on Rust 1.77.2 (Stable), should run on even older builds.

Usage Example:
    let my_buffer: [u8; 42] = randombytes().unwrap();
*/

extern crate getrandom; // https://github.com/rust-random/getrandom

use core::mem::MaybeUninit;

pub fn randombytes<const N: usize>() -> Result<[u8; N], getrandom::Error> {
    // https://github.com/rust-random/rand/issues/1080
    // https://github.com/rust-random/rand/blob/0.8.5/rand_core/src/os.rs#L67
    // https://github.com/rust-random/getrandom/blob/v0.2.14/src/lib.rs#L376
    let mut buf = [MaybeUninit::<u8>::uninit(); N];
    getrandom::getrandom_uninit(&mut buf)?;
    Ok(unsafe {
        // TODO pending https://github.com/rust-lang/rust/issues/96097
        // https://github.com/rust-random/getrandom/blob/v0.2.14/src/util.rs#L4
        // https://github.com/rust-lang/rust/blob/1.77.2/library/core/src/mem/maybe_uninit.rs#L947
        // https://github.com/Lokathor/bytemuck/blob/v1.15.0/src/lib.rs#L113
        // SAFETY: `MaybeUninit<T>` is guaranteed to be layout-compatible with `T`,
        // therefore `[MaybeUninit<T>; N]` is layout-compatible with `[T; N]`.
        // SAFETY: getrandom_uninit returned Ok,
        // therefore buf is guaranteed to be entirely initialized.
        core::mem::transmute_copy(&core::mem::ManuallyDrop::new(buf))
    })
}