nonce method
Implementation
Future<BigInt?> nonce(String identityDid) async {
if (!_matchesExpectedDid(identityDid)) {
throw Exception(
'Information about $identityDid do not belong to this network');
}
var nonceFunction = _erc1056contract.function('nonce');
var nonceValue = await web3Client.call(
contract: _erc1056contract,
function: nonceFunction,
params: [_didToAddress(identityDid)]);
return nonceValue.first as BigInt?;
}