signPersonalMessage method
Implementation
Future<Uint8List> signPersonalMessage(Uint8List message) async {
final prefix = '\x19Ethereum Signed Message:\n${message.length}';
final prefixBytes = Uint8List.fromList(prefix.codeUnits);
final prefixedMessage = Uint8List.fromList(prefixBytes + message);
final hash = crypto.Keccak256.hash(prefixedMessage);
return crypto.Secp256k1.sign(hash, privateKey);
}