public Map<TopicPartition, List<ConsumerRecord<K, V>>> records() {
        final LinkedHashMap<TopicPartition, List<ConsumerRecord<K, V>>> result = new LinkedHashMap<>();
        batches.forEach((tip, batch) -> result.put(tip.topicPartition(), batch.getInFlightRecords()));
        return Collections.unmodifiableMap(result);
    }
@return all the non-control messages for this fetch, grouped by partition
clients/src/main/java/org/apache/kafka/clients/consumer/internals/ShareFetch.java