future.rs

    fn query<R>(&self,
                query: QueryForReply<Id, Definition>,
                reply_rx: oneshot::Receiver<R>)
                -> Box<Future<Item = R, Error = bool>>
        where R: Send + 'static
    {
        self.query_tx
            .clone()
            .send(query)
            .map_err(|_| false)
            .and_then(|_| reply_rx.map_err(|_| false))
            .boxed()
    }