Function futures_util::stream::repeat

pub fn repeat<T>(item: T) -> Repeat<T> where
    T: Clone, 

Create a stream which produces the same item repeatedly.

The stream never terminates. Note that you likely want to avoid usage of collect or such on the returned stream as it will exhaust available memory as it tries to just fill up all RAM.

use futures::prelude::*;
use futures::stream;
use futures::executor::block_on;

let mut stream = stream::repeat(9);
assert_eq!(vec![9, 9, 9], block_on(stream.take(3).collect::<Vec<i32>>()));