Method init

tutorial/MyGNode/MyWriteParamNode.h:17–25

class MyWriteParamNode : public CGraph::GNode {
public:
    CStatus init() override {
        CStatus status;
        /**
         * 推荐在init()中，将可能用到的参数创建好。也支持在run的时候创建
         * 支持在任意节点创建，任意节点读取同类型（MyParam）同名（"param1"）参数
         */
        status = CGRAPH_CREATE_GPARAM(MyParam, "param1")
        return status;
    }

    CStatus run() override {
        /**