跟着官网的rust教程在win10上写的guessing game，cargo run 之后一直显示下面信息：

Blocking waiting for file lock on package cache lock

main.rs的代码：

use std::io;

fn main() {
    println!("Welcome to the guessing game");

    let mut guess = String::new();

    io::stdin().read_line(&mut guess) // &mut indicate a mutable reference
        .expect("Failed to read line");

    println!("You guessed {}", guess); 
}