>which means a lot of unwrapping

     .unwrap()

In rust is generally a bad pattern to use. Its basically short hand for

    let o :Option< u64 >;

    let value :u64 = match o {
                        Some( t ) => t,
                        None => panic!()
                     };

So if you don't met the condition, you explode. When ever you see .unwrap() in Rust just mentally switch it for /TODO add error handling */