/// <summary>
        /// Resume all agent tasks safely.
        /// </summary>
        internal void Resume()
        {
            if (CurrentPacakge == null || CurrentPacakge.State != PackageState.Paused)
            {
                return;
            }

            CurrentPacakge.State  = PackageState.Downloading;
            ParentDownloder.State = DownloaderState.Resumed;

            DownloadSpeedTracker.Start();

            ParentDownloder.CallDownloadResume(CurrentPacakge);
        }
        /// <summary>
        /// Begin all agent tasks safely.
        /// </summary>
        internal async void Begin()
        {
            if (PackageList.Count == 0)
            {
                return;
            }

            System.Console.WriteLine("Devhus.Downloader is beginning...");
            State = AgentState.Busy;
            ParentDownloder.State = DownloaderState.Started;
            ParentDownloder.CallDownloadBegin();
            DownloadSpeedTracker.Start();

            await StartDownloading();
        }