private void persistTxState() {
    LOG.info("Committing state to path [{}] by [{}]", openTxFileName.toString(), writerIdTopicId);
    try (FSDataOutputStream outStream = fileSystem.create(openTxFileName)) {
      outStream.writeLong(producerId);
      outStream.writeShort(producerEpoch);
    } catch (Exception e) {
      sendExceptionRef.compareAndSet(null, e);
    }
  }
Write the Kafka Consumer PID and Epoch to checkpoint file {@link TransactionalKafkaWriter#openTxFileName}.
kafka-handler/src/java/org/apache/hadoop/hive/kafka/TransactionalKafkaWriter.java