pub fn poll_fn<T, F>(f: F) -> PollFn<F>
where
    F: FnMut(&mut Context<'_>) -> Poll<T>,
{
    assert_future::<T, _>(PollFn { f })
}
Creates a new future wrapping around a function returning [`Poll`].

Polling the returned future delegates to the wrapped function.

# Examples

```
# futures::executor::block_on(async {
use futures::future::poll_fn;
use futures::task::{Context, Poll};

fn read_line(_cx: &mut Context<'_>) -> Poll<String> {
Poll::Ready("Hello, World!".into())
}

let read_future = poll_fn(read_line);
assert_eq!(read_future.await, "Hello, World!".to_owned());
# });
```
futures-util/src/future/poll_fn.rs