如何清除或删除Rust中的io::stdin缓冲区？

use std::io;

fn main() {
    let mut input = String::new();
    io::stdin().read_line(&mut input).expect("Failed to read line");
    
    // 清除缓冲区
    let mut temp = String::new();
    io::stdin().read_line(&mut temp).expect("Failed to read line");
}

use std::io::{self, Write};

fn main() {
    let mut input = String::new();
    io::stdin().read_line(&mut input).expect("Failed to read line");
    
    // 清除缓冲区
    io::stdout().flush().unwrap();
}