docs: public static Binary fromHexString(String hex) {
          if (hex.length() % 2 != 0) {
              throw new IllegalArgumentException("Illegal hex string length: " + hex.length());
          }
          final int len = hex.length() / 2;
          final byte[] out = new byte[len];
          for (int i = 0; i < len; ++i) {
              int pos = i * 2;
              String part = hex.substring(pos, pos + 2);
              out[i] = (byte) Integer.parseInt(part, 16);
          }
          return Binary.wrap(out);
      }