You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: smart_pointer.rs
    path of file: ./repos/tao-of-rust-codes/src/ch02
    
    the code of the file until where you have to start completion: /// # 智能指针：Box<T>
///
/// Basic usage:
///
/// ```
/// fn box_demo(){
///     #[derive(PartialEq, Debug)]
///     struct Poi
    
/// fn box_demo(){
///     #[derive(PartialEq, Debug)]
///     struct Point {
///       x: f64,
///       y: f64,
///     }
///     // 将Point实例装箱（放到堆内存）
///     let box_point = Box::new(Point { x: 0.0, y: 0.0 });
///     let unboxed_point: Point = *box_point; // 通过解引用操作符取出Point实例
///     assert_eq!(unboxed_point, Point { x: 0.0, y: 0.0 });
/// }