Function or

pub fn or<T, S1, S2>(stream1: S1, stream2: S2) -> Or<S1, S2>
where
    S1: Stream<Item = T>,
    S2: Stream<Item = T>,

Merges two streams, preferring items from stream1 whenever both streams are ready.

Examples

use futures_lite::stream::{self, once, pending, StreamExt};

assert_eq!(stream::or(once(1), pending()).next().await, Some(1));
assert_eq!(stream::or(pending(), once(2)).next().await, Some(2));

// The first stream wins.
assert_eq!(stream::or(once(1), once(2)).next().await, Some(1));