Method set_start_callback

lite/src/mge/network_impl.h:92–94

set the start callback which will execute before network forward

    //! set the start callback which will execute before network forward
    void set_start_callback(const StartCallback& callback) override {
        m_start_callback = std::move(callback);
    }

    //! set the finish callback which will execute after network forward
    void set_finish_callback(const FinishCallback& callback) override {