private byte[] rawKey(final byte[] data) {
        final byte[] rawKey = new byte[data.length - StateSerdes.TIMESTAMP_SIZE - StateSerdes.BOOLEAN_SIZE];
        System.arraycopy(data, StateSerdes.TIMESTAMP_SIZE + StateSerdes.BOOLEAN_SIZE, rawKey, 0, rawKey.length);
        return rawKey;
    }
The deserializer that is used for {@link TimestampedKeyAndJoinSide}, which is a combo key format of <timestamp, left/right flag, raw-key>
@param <K> the raw key type
streams/src/main/java/org/apache/kafka/streams/state/internals/TimestampedKeyAndJoinSideDeserializer.java