code: byte[][] rawKeys(K key, K otherKey) {
          final byte[][] rawKeys = new byte[2][];
  
          rawKeys[0] = rawKey(key);
          rawKeys[1] = rawKey(key);
          return rawKeys;
      }
docs: Raw keys.
  
  @param key      the key
  @param otherKey the other key
  @return the byte[][]