dubbo3.0.5如何使用stubevent?

我在@DubboReference注解中看到有一项stubevent配置, 并尝试设置为true, @DubboReference(onconnect = "onConnect", stubevent = true, stub = "DemoServiceLocal") 我的本地存根类如下:

package org.apache.dubbo.demo.consumer;

import org.apache.dubbo.demo.DemoService;

public class DemoServiceLocal implements DemoService {

private DemoService demoService;
public DemoServiceLocal(DemoService demoService){
    this.demoService = demoService;
}
@Override
public String sayHello(String name) {
    return demoService.sayHello(name);
}

public void onConnect(){
    System.out.println("DemoServiceLocal.onConnect()");
}

}

按照Provider端的onconnect, ondisconnect事件通知理解, 在Consumer端的存根也支持onconnect, ondisconnect事件 但是Consumer端抛出如下异常:

13:00:59.150 [main] ERROR org.apache.dubbo.rpc.proxy.wrapper.StubProxyFactoryWrapper - [DUBBO] export a stub service error., dubbo version: 3.0.5, current host: 192.168.40.120 java.lang.NullPointerException: null at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:936) at org.apache.dubbo.rpc.support.GroupServiceKeyCache.getServiceKey(GroupServiceKeyCache.java:37) at org.apache.dubbo.rpc.support.ProtocolUtils.serviceKey(ProtocolUtils.java:51) at org.apache.dubbo.rpc.protocol.AbstractProtocol.serviceKey(AbstractProtocol.java:75) at org.apache.dubbo.rpc.protocol.AbstractProtocol.serviceKey(AbstractProtocol.java:71) at org.apache.dubbo.rpc.protocol.dubbo.DubboProtocol.export(DubboProtocol.java:296) at org.apache.dubbo.rpc.protocol.ProtocolListenerWrapper.export(ProtocolListenerWrapper.java:66) at org.apache.dubbo.qos.protocol.QosProtocolWrapper.export(QosProtocolWrapper.java:76) at org.apache.dubbo.rpc.cluster.filter.ProtocolFilterWrapper.export(ProtocolFilterWrapper.java:61) at org.apache.dubbo.rpc.protocol.ProtocolSerializationWrapper.export(ProtocolSerializationWrapper.java:47) at org.apache.dubbo.rpc.Protocol$Adaptive.export(Protocol$Adaptive.java) at org.apache.dubbo.rpc.proxy.wrapper.StubProxyFactoryWrapper.export(StubProxyFactoryWrapper.java:123) at org.apache.dubbo.rpc.proxy.wrapper.StubProxyFactoryWrapper.getProxy(StubProxyFactoryWrapper.java:93) at org.apache.dubbo.rpc.ProxyFactory$Adaptive.getProxy(ProxyFactory$Adaptive.java) at org.apache.dubbo.config.ReferenceConfig.createProxy(ReferenceConfig.java:400) at org.apache.dubbo.config.ReferenceConfig.init(ReferenceConfig.java:275) at org.apache.dubbo.config.ReferenceConfig.get(ReferenceConfig.java:216) at org.apache.dubbo.config.utils.SimpleReferenceCache.get(SimpleReferenceCache.java:110) at org.apache.dubbo.config.deploy.DefaultModuleDeployer.lambda$referServices$6(DefaultModuleDeployer.java:384) at java.util.concurrent.ConcurrentHashMap$ValuesView.forEach(ConcurrentHashMap.java:4707) at org.apache.dubbo.config.deploy.DefaultModuleDeployer.referServices(DefaultModuleDeployer.java:364) at org.apache.dubbo.config.deploy.DefaultModuleDeployer.start(DefaultModuleDeployer.java:151) at org.apache.dubbo.config.deploy.DefaultApplicationDeployer.startModules(DefaultApplicationDeployer.java:617) at org.apache.dubbo.config.deploy.DefaultApplicationDeployer.doStart(DefaultApplicationDeployer.java:581) at org.apache.dubbo.config.deploy.DefaultApplicationDeployer.start(DefaultApplicationDeployer.java:554) at org.apache.dubbo.config.bootstrap.DubboBootstrap.start(DubboBootstrap.java:222) at org.apache.dubbo.config.bootstrap.DubboBootstrap.start(DubboBootstrap.java:212)

原提问者GitHub用户xxxcrel