@Override
    public boolean isFinished() {
        return currentSnapshotSplit == null
                || (!snapshotSplitReadTask.isRunning() && !hasNextElement.get() && reachEnd.get());
    }
Fetcher to fetch data from table split, the split is the snapshot split {@link SnapshotSplit}.
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/reader/external/IncrementalSourceScanFetcher.java