asAuthCode method Null safety
As an AuthCode.
Implementation
AuthCode asAuthCode() {
return AuthCode()
..hasBeenExchanged = accessToken != null
..code = code
..resourceOwnerIdentifier = resourceOwner!.id
..issueDate = issueDate
..requestedScopes = scope?.split(" ").map((s) => AuthScope(s)).toList()
..expirationDate = expirationDate
..clientID = client.id;
}