public Map<String, String> getOffset() {
        return offset;
    }
A structure describes a fine-grained offset in a change event including change log position.

<p>This structure can also be used to deal the change event in transaction, a transaction may
contain multiple change events, and each change event may contain multiple rows. When restart
from a specific {@link Offset}, we need to skip the processed change events and the processed
rows.
Copy from com.ververica:flink-cdc-base:2.3.0.
inlong-sort/sort-flink/cdc-base/src/main/java/org/apache/inlong/sort/cdc/base/source/meta/offset/Offset.java