to_create_struct_scale_encoding.txt

    let mut btree_map: BTreeMap<String, User> = BTreeMap::new();
    match btree_map.entry("string1".to_string()) {
        Entry::Vacant(entry) => {
            entry.insert(User{
                active: true,
                username: "lorem".to_string(),
                email: "lorem@ipsum.org".to_string(),
                sign_in_count: 1,   
             });
            ()
        },
        Entry::Occupied(_) => (),
    }

    match btree_map.entry("string2".to_string()) {
        Entry::Vacant(entry) => {
            entry.insert(User{
                active: false,
                username: "john".to_string(),
                email: "jack@gmail.com".to_string(),
                sign_in_count: 73,   
             });
            ()
        },
        Entry::Occupied(_) => (),
    }

    println!("{:?}", btree_map.encode());