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
}
    
    private URL consumerUrl;
    private List<URL> urls;
    private URL url;
    private String methodName;
    private Class<?>[] parameterTypes;
    private Object[] arguments;
    private InetSocketAddress localAddress;
    private InetSocketAddress remoteAddress;
    private String remoteApplicationName;
    @Deprecated
    private List<Invoker<?>> invokers;
    @Deprecated
    private Invoker<?> invoker;
    @Deprecated
    private Invocation invocation;
    
    
    private Object request;
    private Object response;
    private boolean needPrintRouterSnapshot;
    /**
     * 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
     */
    @Override
    public Object getRequest() {
        return request;