@Override
        public void clear() {
            super.clear();
            number.set(0L);
        }
Initialize {@link NonPreAggPartitionGroupBuffer}

@param rowSchema row data schema
@param partitionKey partition key
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/iceberg/src/main/java/org/apache/inlong/sort/iceberg/sink/collections/PartitionGroupBuffer.java