se1983

use std::thread;
use std::sync::mpsc;

fn main() {
    let (tx, rx) = mpsc::channel();

    let h1 = thread::spawn(move || {
        let val = String::from("hi");
        tx.send(val).unwrap();
    });

se1983

use std::thread;
use std::time::Duration;
use std::collections::HashMap;

struct Cacher<T> where T: Fn(u32) -> u32{
    calculation: T,
    values: HashMap<u32, u32>
}

impl<T> Cacher<T> where T: Fn(u32) -> u32 {