public long currentRows() {
            return currentRows;
        }
Delete those rows with the given key. It will only write the values of equality fields into
the equality-delete file.

@param key is the projected data whose columns are the same as the equality fields.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/iceberg/src/main/java/org/apache/inlong/sort/iceberg/sink/trick/BaseTaskWriter.java