private static async Task<UserCredential> AuthorizeAsyncCore(
GoogleAuthorizationCodeFlow.Initializer initializer, IEnumerable<string> scopes, string user,
CancellationToken taskCancellationToken, IDataStore dataStore = null)
{
initializer.Scopes = scopes;
initializer.DataStore = dataStore ?? new FileDataStore(Folder);
var flow = new GCSMAuthorizationCodeFlow(initializer,user);
// Create an authorization code installed app instance and authorize the user.
return await new AuthorizationCodeInstalledApp(flow, new LocalServerCodeReceiver()).AuthorizeAsync
(user, taskCancellationToken).ConfigureAwait(false);
}