extraClaims property
Extra claims to be added to each access token created for this refresh token.
This is a Map<String, dynamic> where each entry's key is used as a claim name.
The values must be JSON-encodable.
Users must ensure that the claims don't conflict with registered claims or the above-mentioned claim for scopeNames.
This is only stored as a serialized String in the database due to schema limitations.
Implementation
String? extraClaims;