refreshAccessToken method
Use the refresh_token to get a new access_token without asking the user to re-authenticate.
The access_token is valid for 3 months before it needs to be refreshed again.
Implementation
Future<AccessTokenResponse> refreshAccessToken({String? refreshToken}) async {
if (refreshToken != null) {
_manager._refreshToken = refreshToken;
}
if (_manager._refreshToken == null) {
throw Exception("Refresh token is null");
}
return _oauthToken({"refresh_token": _manager._refreshToken!});
}