A example of async input using threads in Rust

async-input.rs

use std::thread;
use std::sync::mpsc::{self, TryRecvError};
use std::io;
use std::time::Instant;

struct CircularIter<T> where T: Copy {
    data: Vec<T>,
    index: usize,
}

impl<T> CircularIter<T> where T: Copy {
    fn new(data: Vec<T>) -> CircularIter<T> {
        CircularIter {
            data,
            index: 0,
        }
    }
}

impl<T> Iterator for CircularIter<T> where T: Copy {
    type Item = T;

    fn next(&mut self) -> Option<Self::Item> {
        if self.data.len() == 0 {
            None
        } else {
            self.index += 1;
            if self.index >= self.data.len() {
                self.index = 0;
            }
            Some(self.data[self.index])
        }
    }
}

fn main() {
    let (tx1, rx1) = mpsc::channel();

    let stdin = io::stdin();
    thread::spawn(move || {
        let mut line = String::new();
        stdin.read_line(&mut line).unwrap();

        tx1.send(()).unwrap();
    });
    
    let progress = CircularIter::new(vec!["―", "\\", "|", "/"]);

    println!();

    'outer: for i in progress {
        let st = Instant::now();
        while st.elapsed().as_millis() < 250 {
            match rx1.try_recv() {
                Ok(_) => {
                    println!("\x1b[2A\x1b[KBye");
                    break 'outer;
                }
                Err(TryRecvError::Disconnected) => break 'outer,
                _ => {}
            }
        }
        println!("\x1b[1AWaiting for input {} ", i);
    }
}