void getBalance() {
  var apiUrl = ""; //Replace with your API

  var httpClient = Client();
  var ethClient = Web3Client(apiUrl, httpClient);

  // EthPrivateKey credentials = EthPrivateKey.fromHex(
  //   '5f87013a9d08deb48850dad3c482f630790ce28d0f15f80ae9a26f172e18c2ca',
  // );

  //EthereumAddress credentials = EthereumAddress(
//    hexToBytes("0x99****77"),
//  );
EthereumAddress credentials = EthereumAddress.fromHex(
    "0x99****77",
  );

  // You can now call rpc methods. This one will query the amount of Ether you own
  Future<EtherAmount> result = ethClient.getBalance(credentials);
  result.then((balance) {
    print(balance.getValueInUnit(EtherUnit.ether));
  }).catchError((e) {
    print(e.toString());
  });
}