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
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package org.apache.dubbo.rpc;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.common.utils.NetUtils;
import org.apache.dubbo.common.utils.StringUtils;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.Future;
import static org.apache.dubbo.common.constants.CommonConstants.CONSUMER_SIDE;
import static org.apache.dubbo.common.constants.CommonConstants.PROVIDER_SIDE;
import static org.apache.dubbo.rpc.Constants.ASYNC_KEY;
import static org.apache.dubbo.rpc.Constants.RETURN_KEY;
public class RpcServiceContext extends RpcContext {
    protected RpcServiceContext() {