cpp20_streams example response printing is incorrect

[anarthal]

        // std::cout << "Response: ";
        // for (int i = 0; i < resp->value().size(); ++i) {
        //     std::cout << resp->value().at(i).value << ", ";
        // }
        // std::cout << std::endl;

        // The following approach was taken in order to be able to
        // deal with the responses, as generated by redis in the case
        // that there are multiple stream 'records' within a single
        // generic_response.  The nesting and number of values in
        // resp.value() are different, depending on the contents
        // of the stream in redis.  Uncomment the above commented-out
        // code for examples while running the XADD command.

Uncomenting the above code causes a build error - should be resp->size() and resp->at()