@Override
    public List<Object> apply(ConsumerRecord<K, V> record) {
        RecordTranslator<K, V> trans = topicToTranslator.getOrDefault(record.topic(), defaultTranslator);
        return trans.apply(record);
    }
@Test
    public void testNullTranslation() {
        ByTopicRecordTranslator<String, String> trans =
                new ByTopicRecordTranslator<>((r) -> null, new Fields("key"));
        ConsumerRecord<String, String> cr = new ConsumerRecord<>("TOPIC 1", 100, 100, "THE KEY", "THE VALUE");
        assertNull(trans.apply(cr));
    }