presto-hive/src/main/java/io/prestosql/plugin/hive/GenericHiveRecordCursorProvider.java/GenericHiveRecordCursorProvider/genericRecordReader
class GenericHiveRecordCursorProvider:    @SuppressWarnings("unchecked")
    private static RecordReader<?, ? extends Writable> genericRecordReader(RecordReader<?, ?> recordReader)
    {
        return (RecordReader<?, ? extends Writable>) recordReader;
    }