你好：
我有一个疑问，当Registry调用destroy后不会去清除AbstractRegistryFactory中的缓存，导致以同样的参数再次获取的时候得到了一个已经无法使用的Registry。这个时设计的时候就认为不该这么使用吗？
*
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.dubbo.registry.support;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.utils.NetUtils;
import org.apache.dubbo.registry.NotifyListener;
import org.apache.dubbo.registry.Registry;
import org.apache.dubbo.registry.RegistryFactory;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import java.util.Collection;
import java.util.List;
/**
 * AbstractRegistryFactoryTest
 *
 */
public class AbstractRegistryFactoryTest {
    private RegistryFactory registryFactory = new AbstractRegistryFactory() {
        @Override
        protected Registry createRegistry(final URL url) {
            return new Registry() {
                public URL getUrl() {
                    return url;
                }
                @Override