use futures::Future; //0.1.28

type AnError = Box<std::error::Error>;

pub trait Test {
    fn do_something(&self) -> Result<(), AnError>;

    fn create_future(&self) -> Box<Future<Item = (), Error = AnError>>;

    fn chain<'a>(&'a self) -> Box<Future<Item = (), Error = AnError> + 'a> {
        Box::new(
            self.create_future()
                .then(move |f| f.and_then(move |_| self.do_something())),
        )
    }
}