如何从Rust (Rocket) HTTP端点返回JSON？

[dependencies]
rocket = "0.5.0-rc.1"
rocket_contrib = "0.5.0-rc.1"
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"

#[macro_use] extern crate rocket;

use rocket_contrib::json::Json;
use serde::Serialize;

#[derive(Serialize)]
struct Person {
    name: String,
    age: u8,
}

#[get("/person")]
fn get_person() -> Json<Person> {
    let person = Person {
        name: String::from("John Doe"),
        age: 30,
    };
    Json(person)
}

#[launch]
fn rocket() -> _ {
    rocket::build().mount("/", routes![get_person])
}

$ cargo run

{
  "name": "John Doe",
  "age": 30
}