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
* get remote address.
     *
     * @return remote address
     */
    @Override
    public InetSocketAddress getRemoteAddress() {
        return remoteAddress;
    }
    /**
     * set remote address.
     *
     * @param address
     * @return context
     */
    @Override
    public RpcServiceContext setRemoteAddress(InetSocketAddress address) {
        this.remoteAddress = address;
        return this;
    }
    @Override
    public String getRemoteApplicationName() {
        return remoteApplicationName;
    }
    @Override
    public RpcServiceContext setRemoteApplicationName(String remoteApplicationName) {
        this.remoteApplicationName = remoteApplicationName;
        return this;
    }
    /**
     * get remote address string.