fn poll_next_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Option<Self::Item>>
    where
        Self: Unpin,
    {
        Pin::new(self).poll_next(cx)
    }
A convenience method for calling [`Stream::poll_next`] on [`Unpin`]
stream types.
futures-util/src/stream/stream/mod.rs