docs: public static Hash merge(Hash a, Hash b) {
          try {
              MessageDigest digest = MessageDigest.getInstance("SHA-256");
              digest.update(a.bytes);
              return Hash.createFromSafeArray(digest.digest(digest.digest(b.bytes)));
          } catch (NoSuchAlgorithmException e) {
              throw new RuntimeException(e);
          }
      }