Method fail

cpp/src/credit_test.cpp:198–204

    }

    void fail(const std::string &msg, int rcv) {
        // Call from work_queue.  Remember the exception later.
        std::ostringstream os;
        os << msg << rcv;
        fail_msg_ = os.str();
        receiver_.connection().close();
    }

    void on_connection_close(proton::connection& c) override {
        if (!fail_msg_.empty())