- [x] I have searched the [issues](https://github.com/apache/incubator-dubbo/issues) of this repository and believe that this is not a duplicate.
- [x] I have checked the [FAQ](https://github.com/apache/incubator-dubbo/blob/master/FAQ.md) of this repository and believe that this is not a duplicate.

### Environment

* Dubbo version: 2.6.4

### Steps to reproduce this issue

1. GenericService泛化调用
2. 使用oninvoke、onreturn、onthrow
3. FutureFilter无法正常回调

### Expected Result
StaticContext.getKey(invoker.getUrl(), invocation.getMethodName(), Constants.ON_INVOKE_METHOD_KEY)
返回
com.alibaba.boot.dubbo.demo.consumer.DemoService:1.0.0.sayHello.oninvoke.method

### Actual Result
StaticContext.getKey(invoker.getUrl(), invocation.getMethodName(), Constants.ON_INVOKE_METHOD_KEY)
返回
com.alibaba.boot.dubbo.demo.consumer.DemoService:1.0.0.$invoke.oninvoke.method

预期是：

```
        String methodName = invocation.getMethodName();
        if("$invoke".equals(methodName)) {
            Object[] arguments = invocation.getArguments();
            methodName = (String) arguments[0];
        }
```

public synchronized T get() {
        checkAndUpdateSubConfigs();
        if (destroyed) {
            throw new IllegalStateException("The invoker of ReferenceConfig(" + url + ") has already destroyed!");
        }
        if (ref == null) {
            init();
        }
        return ref;
    }
    public synchronized void destroy() {
        if (ref == null) {
            return;
        }
        if (destroyed) {
            return;
        }
        destroyed = true;
        try {
            invoker.destroy();
        } catch (Throwable t) {
            logger.warn("Unexpected error occured when destroy invoker of ReferenceConfig(" + url + ").", t);
        }
        invoker = null;
        ref = null;
    }
    private void init() {
        if (initialized) {
            return;
        }