extern crate futures;

use futures::Future;
use futures::future::lazy;
use futures::future::ok;

fn test_send<T, E, F>(f: F) -> Box<Future<Item = T, Error = E>>
where
    F: Future<Item = T, Error = E> + Send + 'static,
{
    Box::new(f)
}

fn main() {
    let f1 = lazy(|_| ok::<u32, u32>(1));
    test_send(f1);

    test_send(lazy(|_| ok::<u32, u32>(1)));

    let f2: Box<Future<Item=u32, Error=u32> + Send> = Box::new(lazy(|_| ok::<u32, u32>(1)));
    test_send(f2);

    //let f3: Box<Future<Item=u32, Error=u32>> = Box::new(lazy(|_| ok::<u32, u32>(1)));
    //test_send(f3);
}