see more from https://github.com/openzipkin/brave/issues/867, also see https://github.com/apache/incubator-dubbo/issues/3576
* @return consumer side.
     */
    public boolean isConsumerSide() {
        return getUrl().getParameter(SIDE_KEY, PROVIDER_SIDE).equals(CONSUMER_SIDE);
    }
    /**
     * get CompletableFuture.
     *
     * @param <T>
     * @return future
     */
    @SuppressWarnings("unchecked")
    public <T> CompletableFuture<T> getCompletableFuture() {
        return (CompletableFuture<T>) future;
    }
    /**
     * get future.
     *
     * @param <T>
     * @return future
     */
    @SuppressWarnings("unchecked")
    public <T> Future<T> getFuture() {
        return (Future<T>) future;
    }
    /**
     * set future.
     *
     * @param future
     */