not support complex struct?

[importcjj]

My cargo.toml

[dependencies]
serde = { version = "1.0", features = ["derive"] }
serde_bytes = "0.10.0"
serde_bencode = { path = "serde-bencode" }

Version of rustc

rustc 1.35.0 (3c235d560 2019-05-20)

And my code

use serde::{Deserialize, Serialize};

use serde_bencode::de;
use serde_bencode::ser;

use std::str;

#[derive(Debug, Deserialize, Serialize)]
struct Node(String, i64);

fn main() {

    let nodes: Vec<Node> = vec![
        Node("aaa".to_owned(), 5665),
        Node("bbb".to_owned(), 5665),
        Node("ccc".to_owned(), 5665),
    ];

    let buffer: Vec<u8> = match ser::to_bytes(&nodes) {
        Ok(s) => s,
        Err(e) => panic!(e),
    };

    println!("{}", str::from_utf8(&buffer).unwrap());


    match de::from_bytes::<Vec<Node>>(&buffer) {
        Ok(t) => {
            // println!("{}", t.len());
            println!("{:?}", t);
        }
        Err(e) => println!("ERROR: {:?}", e),
    };
}

And just got

ll3:aaai5665eel3:bbbi5665eel3:ccci5665eee
[Node("aaa", 5665)]

By the way, I am just a rust noob. Maybe I just made some mistake?