Serialize u32 to bytes and Deserialize u32 from bytes

serialize_u32_to_bytes.rs

/// idea from https://docs.rs/byteorder/1.4.3/src/byteorder/lib.rs.html
#![allow(unused)]
fn main() {
    let mut x: Vec<u8> = Vec::new();
    x.reserve(16);

    let y: u32 = 12;

    unsafe {
        // write y to byte array
        std::ptr::copy_nonoverlapping(
            y.to_ne_bytes().as_ptr(),
            x.as_mut_ptr().offset(8),
            std::mem::size_of::<u32>(),
        );

        // read y from byte array
        let mut y_bytes: [u8; 4] = [0; 4];
        std::ptr::copy_nonoverlapping(
            x.as_ptr().offset(8),
            y_bytes.as_mut_ptr(),
            std::mem::size_of::<u32>(),
        );
        println!("{}", std::mem::transmute::<[u8; 4], u32>(y_bytes));
    }
}