public RedoLogOffset getHighWatermark() {
            return highWatermark;
        }
{@link ChangeEventSource.ChangeEventSourceContext} implementation that keeps low/high
watermark for each {@link SnapshotSplit}.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/oracle-cdc/src/main/java/org/apache/inlong/sort/cdc/oracle/source/reader/fetch/OracleScanFetchTask.java