use std::sync::mpsc::channel;
use std::time::Duration;
use std::thread;

fn init_and_spawn<'a, F, G> (f : F) where
    F: 'a + Send + FnOnce() -> G,
    G: 'static + FnOnce(),
{
    let (send, recv) = channel();
    let boxed = Box::new(f);
    let raw = Box::into_raw(boxed) as usize;
    thread::spawn (move || {
        let boxed = unsafe { Box::from_raw(raw as *mut F) };
        let f = *boxed;
        let g = f();
        let _ = send.send(());
        g()
    });
    let _ = recv.recv();
}

fn main() {
    let ref hello = String::from("hello");
    init_and_spawn(|| {
        let clone = hello.clone();
        move || {
            println!("{}", clone);
        }
    });
    thread::sleep(Duration::from_millis(1000));
}