public Map<String, List<PartitionInfo>> getAllTopicMetadata(Timer timer) {
        MetadataRequest.Builder request = MetadataRequest.Builder.allTopics();
        return getTopicMetadata(request, timer);
    }
@Test
    public void testGetAllTopicsTimeout() {
        // since no response is prepared, the request should time out
        buildFetcher();
        assignFromUser(singleton(tp0));
        assertThrows(TimeoutException.class, () -> topicMetadataFetcher.getAllTopicMetadata(time.timer(50L)));
    }