@Override
  public FileSplit createMergeSplit(Configuration conf,
                                    CombineHiveInputFormat.CombineHiveInputSplit split,
                                    Integer partition, Properties properties) throws IOException {
    return new IcebergMergeSplit(conf, split, partition, properties);
  }
Converts Hive filter found in the passed job conf to an Iceberg filter expression. Then evaluates this
against the task's partition value producing a residual filter expression.
@param task - file scan task to evaluate the expression against
@param conf - job conf
@return - Iceberg residual filter expression
iceberg/iceberg-handler/src/main/java/org/apache/iceberg/mr/hive/HiveIcebergInputFormat.java