Function futures_util::stream::poll_fn [−][src]
pub fn poll_fn<T, F>(f: F) -> PollFn<F> where
F: FnMut(&mut Context<'_>) -> Poll<Option<T>>,
Creates a new stream wrapping a function returning Poll<Option<T>>
.
Polling the returned stream calls the wrapped function.
Examples
use futures::stream::poll_fn; use futures::task::Poll; let mut counter = 1usize; let read_stream = poll_fn(move |_| -> Poll<Option<String>> { if counter == 0 { return Poll::Ready(None); } counter -= 1; Poll::Ready(Some("Hello, World!".to_owned())) });