public long get(long epoch) {
        if (epoch == SnapshotRegistry.LATEST_EPOCH) return value;
        Iterator<Snapshot> iterator = snapshotRegistry.iterator(epoch);
        while (iterator.hasNext()) {
            Snapshot snapshot = iterator.next();
            LongContainer container = snapshot.getDelta(TimelineLong.this);
            if (container != null) return container.value();
        }
        return value;
    }
This is a mutable long which can be snapshotted.
<br>
This class requires external synchronization.
server-common/src/main/java/org/apache/kafka/timeline/TimelineLong.java