使用预定义令牌初始化google api v3 calendarservice

Question

我有一个服务器应用程序需要读取用户日历的所有日历条目。用户已经授权，我已将authcode和刷新令牌存储在我的服务器数据库中。我可以使用已保存的oauth2令牌初始化日历api v3日历服务吗？如果不在运行时请求用户授权，我无法弄清楚如何使其工作。

我有这个工作，但我无法确定如何使用预定义的令牌来初始化服务。

            Dim myscopes As String() = New String() {CalendarService.Scope.Calendar} ' New () {CalendarService.Scope.Calendar}
        Dim secrets As New ClientSecrets() With { _
             .ClientId = rs.OAuth2Parameters.ClientId, _
             .ClientSecret = rs.OAuth2Parameters.ClientSecret _
        }
        Dim credential As UserCredential = GoogleWebAuthorizationBroker.AuthorizeAsync(secrets, myscopes, "sellggltest1@gmail.com", System.Threading.CancellationToken.None).Result

        Dim service = New CalendarService(New BaseClientService.Initializer() With { _
             .HttpClientInitializer = credential, _
             .ApplicationName = rs.Application _
        })


        Dim request As CalendarListResource.ListRequest = service.CalendarList.List()
        Dim events As Data.CalendarList = request.Execute()