see more from https://github.com/openzipkin/brave/issues/867, also see https://github.com/apache/incubator-dubbo/issues/3576
* Get the response object of the underlying RPC protocol, e.g. HttpServletResponse
     *
     * @return null if the underlying protocol doesn't provide support for getting response
     */
    public Object getResponse() {
        return response;
    }
    public void setResponse(Object response) {
        this.response = response;
    }
    /**
     * Get the response object of the underlying RPC protocol, e.g. HttpServletResponse
     *
     * @return null if the underlying protocol doesn't provide support for getting response or the response is not of the specified type
     */
    @SuppressWarnings("unchecked")
    public <T> T getResponse(Class<T> clazz) {
        return (response != null && clazz.isAssignableFrom(response.getClass())) ? (T) response : null;
    }
    /**
     * is provider side.
     *
     * @return provider side.
     */
    public boolean isProviderSide() {
        return !isConsumerSide();
    }
    /**
     * is consumer side.
     *