pub fn poll_once<T, F>(f: F) -> PollOnce<F>where F: Future<Output = T>,
Polls a future just once and returns an Option with the result.
Option
use futures_lite::future; assert_eq!(future::poll_once(future::pending::<()>()).await, None); assert_eq!(future::poll_once(future::ready(42)).await, Some(42));