use futures::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
#[allow(dead_code)]
pub(crate) fn select_lite<A, B>(a: A, b: B) -> SelectLite<A, B> {
SelectLite { a, b }
}
pub(crate) struct SelectLite<A, B> {
a: A,
b: B,
}
impl<A: Future, B: Future<Output = A::Output>> Future for SelectLite<A, B> {
type Output = A::Output;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
unsafe {
let self_mut = self.get_unchecked_mut();
if let Poll::Ready(a) = Pin::new_unchecked(&mut self_mut.a).poll(cx) {
return Poll::Ready(a);
}
if let Poll::Ready(b) = Pin::new_unchecked(&mut self_mut.b).poll(cx) {
return Poll::Ready(b);
}
Poll::Pending
}
}
}