@Override public ConsumerRecord<byte[], byte[]> next() {
    ConsumerRecord<byte[], byte[]> value = nextRecord;
    Preconditions.checkState(value.offset() < endOffset);
    findNext();
    return value;
  }
Poll more records from the Kafka Broker.

@throws PollTimeoutException if poll returns 0 record  and consumer's position < requested endOffset.
kafka-handler/src/java/org/apache/hadoop/hive/kafka/KafkaRecordIterator.java