byte[] fetch(final Bytes key, final long timestamp, final int seqnum) {
        return get(TimeFirstWindowKeySchema.toStoreKeyBinary(key, timestamp, seqnum));
    }
A RocksDB backed time-ordered segmented bytes store for window key schema.
streams/src/main/java/org/apache/kafka/streams/state/internals/RocksDBTimeOrderedWindowSegmentedBytesStore.java