docs: public static String toChecksumAddress(String address) {
          String lowercaseAddress = Numeric.cleanHexPrefix(address).toLowerCase();
          String addressHash = Numeric.cleanHexPrefix(Hash.sha3String(lowercaseAddress));
  
          StringBuilder result = new StringBuilder(lowercaseAddress.length() + 2);
  
          result.append("0x");
  
          for (int i = 0; i < lowercaseAddress.length(); i++) {
              if (Integer.parseInt(String.valueOf(addressHash.charAt(i)), 16) >= 8) {
                  result.append(String.valueOf(lowercaseAddress.charAt(i)).toUpperCase());
              } else {
                  result.append(lowercaseAddress.charAt(i));
              }
          }
  
          return result.toString();
      }