static Window extractStoreWindow(final byte[] binaryKey,
                                     final long windowSize) {
        final ByteBuffer buffer = ByteBuffer.wrap(binaryKey);
        final long start = buffer.getLong(binaryKey.length - TIMESTAMP_SIZE - SEQNUM_SIZE);
        return timeWindowForSize(start, windowSize);
    }
Safely construct a time window of the given size,
taking care of bounding endMs to Long.MAX_VALUE if necessary
streams/src/main/java/org/apache/kafka/streams/state/internals/WindowKeySchema.java