presto-main/src/main/java/io/prestosql/split/MappedRecordSet.java/MappedRecordCursor/MappedRecordCursor
class MappedRecordCursor:        private MappedRecordCursor(RecordCursor delegate, int[] delegateFieldIndex)
        {
            this.delegate = delegate;
            this.delegateFieldIndex = delegateFieldIndex;
        }