@Override
    public ConsumerBuilder<T> topic(String... topicNames) {
        checkArgument(topicNames != null && topicNames.length > 0,
                "Passed in topicNames should not be null or empty.");
        return topics(Arrays.stream(topicNames).collect(Collectors.toList()));
    }
@Test(expectedExceptions = IllegalArgumentException.class)
    public void testConsumerBuilderImplWhenTopicNamesVarargsHasBlankTopic() {
        consumerBuilderImpl.topic("my-topic", "  ");
    }