现象：从日志图片看，进入回调间隔2251ms后，后续马上0ms间隔处理完队列中对接的数据。

    void start_publishers() {
        for (auto& [name, topic] : topics_) {
          
            auto qos = rclcpp::QoS(
                        rclcpp::QoSInitialization(RMW_QOS_POLICY_HISTORY_KEEP_LAST, 40));
            qos.reliability(RMW_QOS_POLICY_RELIABILITY_RELIABLE);
            qos.durability(RMW_QOS_POLICY_DURABILITY_TRANSIENT_LOCAL);

            // 创建发布者
            if (topic.type == "pointcloud") {
                topic.publisher = this->create_publisher<sensor_msgs::msg::PointCloud2>(name, qos);
            } else if (topic.type == "feedback_status") {
                topic.publisher = this->create_publisher<ros_sms_msgs::msg::FeedbackStatus>(name, qos);
            }

            // 计算发布周期（毫秒）
            auto period_ms = std::chrono::milliseconds((int)(1000.0 / topic.frequency));
            
            // 创建定时器，控制发布频率
            topic.timer = this->create_wall_timer(
                period_ms,
                [this, &topic]() {
                    publish_message(topic);
                }
            );
        }
    }

SubDifftime(const std::string & topic_name)
    {
      // 取topic最后3个字符作为节点名称的一部分
      std::string suffix = topic_name.substr(topic_name.length() - 3);
      std::string node_name = "sub_difftime_" + suffix;
      node_ = std::make_shared<rclcpp::Node>(node_name);

      auto qos = rclcpp::QoS(
        rclcpp::QoSInitialization(RMW_QOS_POLICY_HISTORY_KEEP_LAST, 40));
      qos.reliability(RMW_QOS_POLICY_RELIABILITY_RELIABLE);
      
      subscriber_ = node_->create_subscription<sensor_msgs::msg::PointCloud2>(
        topic_name,
        qos,  // 使用自定义QoS配置
        std::bind(&SubDifftime::callback, this, std::placeholders::_1)
      );

      RCLCPP_INFO(node_->get_logger(), "Subscribing to topic: %s", topic_name.c_str());

#if 1
      rclcpp::executors::MultiThreadedExecutor executor(rclcpp::ExecutorOptions(), 12);
      executor.add_node(node_);

      
      while (rclcpp::ok()) {
        executor.spin_once(std::chrono::milliseconds(10));  // 每次阻塞10ms，检查是否有新消息
        // 或直接 executor.spin(); （完全阻塞，直到节点退出）
      }
      executor.remove_node(node_);
#else
      rclcpp::spin(node_);
#endif
    };