presto-kafka/src/main/java/io/prestosql/plugin/kafka/KafkaRecordSetProvider.java/KafkaRecordSetProvider/getRecordSet
class KafkaRecordSetProvider:    @Override
    public RecordSet getRecordSet(ConnectorTransactionHandle transaction, ConnectorSession session, ConnectorSplit split, ConnectorTableHandle table, List<? extends ColumnHandle> columns)
    {
        KafkaSplit kafkaSplit = convertSplit(split);

        List<KafkaColumnHandle> kafkaColumns = columns.stream()
                .map(KafkaHandleResolver::convertColumnHandle)
                .collect(ImmutableList.toImmutableList());

        RowDecoder keyDecoder = decoderFactory.create(
                kafkaSplit.getKeyDataFormat(),
                getDecoderParameters(kafkaSplit.getKeyDataSchemaContents()),
                kafkaColumns.stream()
                        .filter(col -> !col.isInternal())
                        .filter(KafkaColumnHandle::isKeyDecoder)
                        .collect(toImmutableSet()));

        RowDecoder messageDecoder = decoderFactory.create(
                kafkaSplit.getMessageDataFormat(),
                getDecoderParameters(kafkaSplit.getMessageDataSchemaContents()),
                kafkaColumns.stream()
                        .filter(col -> !col.isInternal())
                        .filter(col -> !col.isKeyDecoder())
                        .collect(toImmutableSet()));

        return new KafkaRecordSet(kafkaSplit, consumerManager, kafkaColumns, keyDecoder, messageDecoder);
    }