/// <summary>
        /// 开始下载 和 上传
        /// </summary>
        /// <param name="cloudid"></param>
        /// <param name="source"></param>
        /// <param name="target"></param>
        /// <param name="operaType"></param>
        /// <returns></returns>
        public static Task <bool> Start(Guid cloudid, FileInformation source, string target, OperaType operaType)
        {
            var cloud = GetCloud(cloudid);

            RefreshCloudToken(cloudid);

            var cancel = new CancellationTokenSource();
            var token  = cancel.Token;
            var result = Task.Factory.StartNew(() =>
            {
                token.ThrowIfCancellationRequested();
                return(cloud?.Start(source, target, operaType));
            },
                                               token);

            if (result.Result.Result)
            {
                TaskManagement.AddTask(Path.Combine(source.FilePath, source.FileName),
                                       result,
                                       cancel,
                                       target,
                                       0,
                                       cloudid);
                return(result.Result);
            }
            return(result.Result);
        }
        /// <summary>
        /// 暂停下载
        /// </summary>
        /// <param name="cloudid"></param>
        /// <param name="taskid"></param>
        public static void Pause(Guid cloudid, string taskid)
        {
            var task = TaskManagement.GetOneTask(Guid.Parse(taskid));

            task.CancelSignal.Cancel();
        }