use std::convert::TryInto;

#[derive(Default, Debug, Clone, Copy)]
#[repr(C, packed)]
struct Header {
    timestamp_ns: i64,
    message_id: u16,
    message_version: u16,
    sequence_number: u16,
    reserved: [u32;10],
    length_bytes: u16,
}

fn main() {
    let mut header = Header::default();
    header.message_id = 4;
    header.length_bytes = 42;

    let bytes: [u8; std::mem::size_of::<Header>()] = unsafe { std::mem::transmute(header) };
    // println!("{:?}", bytes);

    // Now say you only have a byte slice
    let byte_slice: &[u8] = &bytes[..];

    let header_again: &Header = unsafe { std::mem::transmute(byte_slice.as_ptr()) };
    println!("{:?}", header_again);
}