pub fn poll_fn<T, F>(f: F) -> PollFn<F>where F: FnMut(&mut Context<'_>) -> Poll<Option<T>>,
Creates a stream from a function returning Poll.
Poll
use futures_lite::stream::{self, StreamExt}; use std::task::{Context, Poll}; fn f(_: &mut Context<'_>) -> Poll<Option<i32>> { Poll::Ready(Some(7)) } assert_eq!(stream::poll_fn(f).next().await, Some(7));