sign method
Implementation
@override
Future<Map<String, dynamic>> sign(PublicKeyCredentialRequestOptions publicKey) async {
try {
final jsOptions = publicKey.toJson().jsify();
final result = await _sign(jsOptions).toDart;
return (result.dartify() as Map<Object?, Object?>).cast<String, dynamic>();
} catch (e) {
throw Exception('Sign failed: $e');
}
}