signMessage

Future<String> signMessage({
  required String chainId,
  required String message,
})

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

final signature = await portal.signMessage(
  chainId: 'eip155:1',
  message: 'Hello, Portal!',
);

print('Signature: $signature');

try {
  final signature = await portal.signMessage(
    chainId: 'eip155:1',
    message: 'Hello, Portal!',
  );
} on PortalException catch (e) {
  print('Failed to sign message: ${e.code} - ${e.message}');
}