) -> impl futures::Future<Output = Result<(Self, crate::signature::Signature), Error>> {

    ) -> impl futures::Future<Output = (Self, Result<crate::signature::Signature, Error>)> {

            self.read_response().await?;

            if let Err(e) = self.read_response().await {
                return (self, Err(e));
            }

                let sig: Result<crate::signature::Signature, Error> = {
                    let mut r = self.buf.reader(1);

                let as_sig = |buf: &CryptoVec| -> Result<crate::signature::Signature, Error> {
                    let mut r = buf.reader(1);

                Ok((self, sig?))

                let sig = as_sig(&self.buf);
                (self, sig)

                Err(Error::AgentProtocolError.into())

                (self, Err(Error::AgentProtocolError.into()))