C# WinApp HttpClient Stream รบกวนช่วยดูโค้ดให้หน่อยครับ

for (int i = 0; i < dataGridView1.RowCount - 1; i++)
            {
                try
                {

                    int rowIndex = i;
                    //  Task t = factory.StartNew( async()=> {

                    var client = new HttpClient();
                    long? totalByte = 0;
                    string name = txtOutput.Text + "\\" + dataGridView1[1, rowIndex].Value.ToString() + ".mp4";
                    string nameTemp = Path.GetTempPath() + "SongLoad\\" + dataGridView1[1, rowIndex].Value.ToString() + ".mp4";
                    string nameMP3 = txtOutput.Text + "\\" + dataGridView1[1, rowIndex].Value.ToString() + ".mp3";

                    if (File.Exists(name) || File.Exists(nameMP3))
                    {
                        dataGridView1.Invoke((MethodInvoker)(() => dataGridView1[5, rowIndex].Value = 100));
                        //  return;
                    }
                    else
                    {

                        Directory.CreateDirectory(Path.GetDirectoryName(nameTemp));
                        Directory.CreateDirectory(Path.GetDirectoryName(name));
                        var vid = youTube.GetVideo(dataGridView1[2, rowIndex].Value.ToString());
                        dataGridView1.Invoke((MethodInvoker)(() => dataGridView1[5, rowIndex].Value = 0));

                        long totalbytes = 0;
                        long collectedbytes = 0;


                        using (Stream output = File.OpenWrite(nameTemp))
                        {
                            using (var request = new HttpRequestMessage(HttpMethod.Head, vid.Uri))
                            {
                                totalByte = client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead).Result.Content.Headers.ContentLength;
                            }
                            totalbytes += (long)totalByte;
                            using (var input = await client.GetStreamAsync(vid.Uri))
                            {
                                byte[] buffer = new byte[16 * 1024];
                                int read;
                                int totalRead = 0;

                                while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
                                {
                                    output.Write(buffer, 0, read);
                                    totalRead += read;
                                    collectedbytes += read;
                                    long x = collectedbytes * 80 / totalbytes;
                                    //  this.toolStripStatusLabel1.Text = TORServices.PathFile.FileTor.bytetobigger(collectedbytes) + "/" + TORServices.PathFile.FileTor.bytetobigger(totalbytes);
                                    dataGridView1.Invoke((MethodInvoker)(() => dataGridView1[5, rowIndex].Value = (int)x));


                                }
                            }
                        }
                        if (SoundOnly.Checked)
                        {
                            _ = Task.Run(() => ConverttoMp3(nameTemp,nameMP3));
                        }
                        else
                        {
                            try
                            {
                                File.Move(nameTemp, name);
                                dataGridView1.Invoke((MethodInvoker)(() => dataGridView1[5, rowIndex].Value = 100));
                            }
                            catch { }
                        }


                     
                        this.toolStripProgressBar1.Value++;
                        client.Dispose();
                    }
                        

                  //  }, cts.Token);
                 //    tasks.Add(t);

                }
                catch
                {
                   dataGridView1.Invoke((MethodInvoker)(() => dataGridView1[5, i].Value = 100));

                }

            }