Method done

tenseal/cpp/utils/queue.h:50–56

* done() notifies all listeners to shutdown. **/

     * done() notifies all listeners to shutdown.
     **/
    void done() noexcept {
        {
            std::scoped_lock lock{mutex_};
            done_ = true;
        }
        ready_.notify_all();
    }
    /**
     * empty() returns if the queue is empty or not.
     **/