减少异步方法，换成尝试读取方法

Author: lindexi

src/dotnetCampus.FileDownloader/DownloadByHttpClient/SegmentFileDownloaderByHttpClient.cs

@@ -573,7 +573,12 @@ private async ValueTask DownloadTask()
                     return;
                 }
 
-                data = await DownloadDataList.Reader.ReadAsync().ConfigureAwait(false);
+                if (!DownloadDataList.Reader.TryRead(out data))
+                {
+                    // 居然读取不到数据，那就再次进入循环吧
+                    continue;
+                }
+
                 Interlocked.Decrement(ref _workTaskCount);
             }
             catch (ChannelClosedException)