Couldn't help but notice, F' as u8 is equivalent to b'F' , and ['F' as u8, 'R' as u8, 'E' as u8, 'E' as u8] is equivalent to *b"FREE" wh

Couldn't help but notice, F' as u8 is equivalent to b'F' , and ['F' as u8, 'R' as u8, 'E' as u8, 'E' as u8] is equivalent to *b"FREE" which definitely is a lot more concise :). These are called byte string literals. Edit: The dereference is necessary because b"FREE" on its own has the type &[u8; 4].