首先是dubbo的泛化广播调用，泛化调用方式为GSON
然后不是有个全链路追踪插件叫 sofa-tracer 嘛，sofa-tracer的dubbo filter拦截器工作时候，要从 RpcContext.getUrl()，但是发现get出来是个空导致空指针
![image](https://user-images.githubusercontent.com/42512469/195077820-0731c73e-bb4f-4088-9142-8e3abbde29c1.png)

但是我用常规自带的广播调用模式，就没问题，只有 broadcastCluster1Invoker 有问题
        <dependency>
            <groupId>org.apache.dubbo.extensions</groupId>
            <artifactId>dubbo-cluster-broadcast-1</artifactId>
            <version>1.0.0</version>
            <scope>provided</scope>
        </dependency>
就是上面这种，有问题
}
    @Override
    public void setRequest(Object request) {
        this.request = request;
    }
    /**
     * Get the request object of the underlying RPC protocol, e.g. HttpServletRequest
     *
     * @return null if the underlying protocol doesn't provide support for getting request or the request is not of the specified type
     */
    @Override
    @SuppressWarnings("unchecked")
    public <T> T getRequest(Class<T> clazz) {
        return (request != null && clazz.isAssignableFrom(request.getClass())) ? (T) request : null;
    }
    /**
     * Get the response object of the underlying RPC protocol, e.g. HttpServletResponse
     *
     * @return null if the underlying protocol doesn't provide support for getting response
     */
    @Override
    public Object getResponse() {
        return response;
    }
    @Override
    public void setResponse(Object response) {
        this.response = response;
    }
    /**
     * Get the response object of the underlying RPC protocol, e.g. HttpServletResponse