public void seal() throws IOException {
        if (!update) {
            return;
        }
        saveInfo(segmentPath, new Metadata(version(), mode.name(), rowCount), segmentSchema);
        for (DPColumn col : columns) {
            col.seal();
        }
        update = false;
    }
End up update this Segment. Flush the cache to file and close the open files.
After this call, any ingesting operation will rise exceptions.
indexr-segment/src/main/java/io/indexr/segment/storage/DPSegment.java