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    use core::pin::Pin;
    use futures_core::ready;
    use futures_core::stream::{FusedStream, Stream};
    use futures_core::task::{Context, Poll};
    #[cfg(feature = "sink")]
    use futures_sink::Sink;
    use pin_project_lite::pin_project;

    pin_project! {
        /// Stream for the [`enumerate`](super::StreamExt::enumerate) method.
        #[derive(Debug)]
        #[must_use = "streams do nothing unless polled"]
        pub struct Enumerate<St> {
            #[pin]
            stream: St,
            count: usize,
        }
    }

    impl<St: Stream> Enumerate<St> {
        pub(super) fn new(stream: St) -> Self {
            Self {
                stream,
                count: 0,
            }
        }

        delegate_access_inner!(stream, St, ());
    }

    impl<St: Stream + FusedStream> FusedStream for Enumerate<St> {
        fn is_terminated(&self) -> bool {
            self.stream.is_terminated()
        }
    }

    impl<St: Stream> Stream for Enumerate<St> {
        type Item = (usize, St::Item);

        fn poll_next(
            self: Pin<&mut Self>,
            cx: &mut Context<'_>,
        ) -> Poll<Option<Self::Item>> {
            let this = self.project();

            match ready!(this.stream.poll_next(cx)) {
                Some(item) => {
                    let prev_count = *this.count;
                    *this.count += 1;
                    Poll::Ready(Some((prev_count, item)))
                }
                None => Poll::Ready(None),
            }
        }

        fn size_hint(&self) -> (usize, Option<usize>) {
            self.stream.size_hint()
        }
    }

    // Forwarding impl of Sink from the underlying stream
    #[cfg(feature = "sink")]
    impl<S, Item> Sink<Item> for Enumerate<S>
    where
        S: Stream + Sink<Item>,
    {
        type Error = S::Error;

        delegate_sink!(stream, Item);
    }