private static async Task UploadFile(FileTransferTask task)
 {
     if (await QiniuService.UploadFile(task))
     {
         RemoveTaskById(task.TaskId);
     }
 }
        private static async Task DownloadFile(FileTransferTask task)
        {
            await QiniuService.DownloadFile(task);

            RemoveTaskById(task.TaskId);
        }