struct One {
      foo: u8,
    }
    
    struct Two {
      bar: u16,
    }
    
    struct Three {
      foo: u8,
      bar: u16,
    }
    
    struct Four {
      foo: u16,
      bar: u16,
    }
    
    fn main() {
        assert_eq!(1, std::mem::size_of::<One>());
        assert_eq!(2, std::mem::size_of::<Two>());
        assert_eq!(4, std::mem::size_of::<Three>());
        assert_eq!(4, std::mem::size_of::<Four>());
    }