Function futures::future::lazy

pub fn lazy<F, R>(f: F) -> Lazy<F> where
    F: FnOnce(&mut Context) -> R, 

Creates a new future from a closure.

The provided closure is only run once the future is polled.

Examples

use futures::prelude::*;
use futures::future;

let a = future::lazy(|_| 1);

let b = future::lazy(|_| -> i32 {
    panic!("oh no!")
});
drop(b); // closure is never run