presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/RaptorNodePartitioningProvider.java/RaptorNodePartitioningProvider/getBucketFunction
class RaptorNodePartitioningProvider:    @Override
    public BucketFunction getBucketFunction(ConnectorTransactionHandle transaction, ConnectorSession session, ConnectorPartitioningHandle partitioning, List<Type> partitionChannelTypes, int bucketCount)
    {
        return new RaptorBucketFunction(bucketCount, partitionChannelTypes);
    }