docs: private FlinkKafkaProducer<byte[], byte[]> createTransactionalProducer() throws FlinkKafka011Exception {
  		String transactionalId = availableTransactionalIds.poll();
  		if (transactionalId == null) {
  			throw new FlinkKafka011Exception(
  				FlinkKafka011ErrorCode.PRODUCERS_POOL_EMPTY,
  				"Too many ongoing snapshots. Increase kafka producers pool size or decrease number of concurrent checkpoints.");
  		}
  		FlinkKafkaProducer<byte[], byte[]> producer = initTransactionalProducer(transactionalId, true);
  		producer.initTransactions();
  		return producer;
  	}