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    use {Stream, Poll};

    /// Do something with the error of a stream, passing it on.
    ///
    /// This is created by the `Stream::inspect_err` method.
    #[derive(Debug)]
    #[must_use = "streams do nothing unless polled"]
    pub struct InspectErr<S, F> where S: Stream {
        stream: S,
        inspect: F,
    }

    pub fn new<S, F>(stream: S, f: F) -> InspectErr<S, F>
        where S: Stream,
              F: FnMut(&S::Error) -> (),
    {
        InspectErr {
            stream: stream,
            inspect: f,
        }
    }

    impl<S: Stream, F> InspectErr<S, F> {
        /// Acquires a reference to the underlying stream that this combinator is
        /// pulling from.
        pub fn get_ref(&self) -> &S {
            &self.stream
        }

        /// Acquires a mutable reference to the underlying stream that this
        /// combinator is pulling from.
        ///
        /// Note that care must be taken to avoid tampering with the state of the
        /// stream which may otherwise confuse this combinator.
        pub fn get_mut(&mut self) -> &mut S {
            &mut self.stream
        }

        /// Consumes this combinator, returning the underlying stream.
        ///
        /// Note that this may discard intermediate state of this combinator, so
        /// care should be taken to avoid losing resources when this is called.
        pub fn into_inner(self) -> S {
            self.stream
        }
    }

    // Forwarding impl of Sink from the underlying stream
    impl<S, F> ::sink::Sink for InspectErr<S, F>
        where S: ::sink::Sink + Stream
    {
        type SinkItem = S::SinkItem;
        type SinkError = S::SinkError;

        fn start_send(&mut self, item: S::SinkItem) -> ::StartSend<S::SinkItem, S::SinkError> {
            self.stream.start_send(item)
        }

        fn poll_complete(&mut self) -> Poll<(), S::SinkError> {
            self.stream.poll_complete()
        }

        fn close(&mut self) -> Poll<(), S::SinkError> {
            self.stream.close()
        }
    }

    impl<S, F> Stream for InspectErr<S, F>
        where S: Stream,
              F: FnMut(&S::Error),
    {
        type Item = S::Item;
        type Error = S::Error;

        fn poll(&mut self) -> Poll<Option<S::Item>, S::Error> {
            self.stream.poll().map_err(|e| {
                (self.inspect)(&e);
                e
            })
        }
    }

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