Method init

example/E01-AutoPilot.cpp:74–78

class LaneDetectorGNode : public GNode {
public:
    CStatus init() override {
        // 订阅 EXAMPLE_IMAGE_TOPIC 消息。每次 bind的返回值，是不一样的，用于区分
        conn_id_ = CGRAPH_BIND_MESSAGE_TOPIC(ImageMParam, EXAMPLE_IMAGE_TOPIC, DEFAULT_MESSAGE_BUF_SIZE)
        return CStatus();
    }

    CStatus run() override {
        std::shared_ptr<ImageMParam> image = nullptr;