docs: public static HashCode fromString(String string) {
      checkArgument(
          string.length() >= 2, "input string (%s) must have at least 2 characters", string);
      checkArgument(
          string.length() % 2 == 0,
          "input string (%s) must have an even number of characters",
          string);
  
      byte[] bytes = new byte[string.length() / 2];
      for (int i = 0; i < string.length(); i += 2) {
        int ch1 = decode(string.charAt(i)) << 4;
        int ch2 = decode(string.charAt(i + 1));
        bytes[i / 2] = (byte) (ch1 + ch2);
      }
      return fromBytesNoCopy(bytes);
    }