private boolean internalPosDelete(StructLike key) {
            BaseTaskWriter.PathOffset previous = insertedRowMap.remove(key);

            if (previous != null) {
                // TODO attach the previous row if has a positional-delete row schema in appender factory.
                posDeleteWriter.delete(previous.path, previous.rowOffset, null);
                return true;
            }

            return false;
        }
Write the pos-delete if there's an existing row matching the given key.

@param key has the same columns with 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