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    use {Future, Poll};

    /// Combines two different futures yielding the same item and error
    /// types into a single type.
    #[derive(Debug)]
    pub enum Either<A, B> {
        /// First branch of the type
        A(A),
        /// Second branch of the type
        B(B),
    }

    impl<T, A, B> Either<(T, A), (T, B)> {
        /// Splits out the homogeneous type from an either of tuples.
        ///
        /// This method is typically useful when combined with the `Future::select2`
        /// combinator.
        pub fn split(self) -> (T, Either<A, B>) {
            match self {
                Either::A((a, b)) => (a, Either::A(b)),
                Either::B((a, b)) => (a, Either::B(b)),
            }
        }
    }

    impl<A, B> Future for Either<A, B>
        where A: Future,
              B: Future<Item = A::Item, Error = A::Error>
    {
        type Item = A::Item;
        type Error = A::Error;

        fn poll(&mut self) -> Poll<A::Item, A::Error> {
            match *self {
                Either::A(ref mut a) => a.poll(),
                Either::B(ref mut b) => b.poll(),
            }
        }
    }

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