@Override
    public void append(List<T> records) {
        if (snapshot.isFrozen()) {
            String message = String.format(
                "Append not supported. Snapshot is already frozen: id = '%s'.",
                snapshot.snapshotId()
            );

            throw new IllegalStateException(message);
        }

        accumulator.append(snapshot.snapshotId().epoch(), records, OptionalLong.empty(), false);

        if (accumulator.needsDrain(time.milliseconds())) {
            appendBatches(accumulator.drain());
        }
    }
Adds a {@link SnapshotFooterRecord} to the snapshot

No more records should be appended to the snapshot after calling this method
raft/src/main/java/org/apache/kafka/snapshot/RecordsSnapshotWriter.java