DataFromSites.DownloadFileWithSupportOfResume Method

public static void DownloadFileWithSupportOfResume(string sourceFileUrl,
     string targetFile)
 {
     long iFileSize = 0;
     int iBufferSize = 1024;
     iBufferSize *= 1000;
     long iExistLen = 0;
     FileStream saveFileStream;
     if (File.Exists(targetFile))
     {
         FileInfo fINfo = new FileInfo(targetFile);
         iExistLen = fINfo.Length;
     }
     if (iExistLen > 0)
         saveFileStream = new FileStream(targetFile,
           FileMode.Append,
           FileAccess.Write,
           FileShare.ReadWrite);
     else
         saveFileStream = new FileStream(targetFile,
           FileMode.Create,
           FileAccess.Write,
           FileShare.ReadWrite);
     HttpWebRequest hwRq;
     HttpWebResponse hwRes;
     hwRq = (HttpWebRequest)WebRequest.Create(sourceFileUrl);
     hwRq.AddRange((int)iExistLen);
     Stream smRespStream;
     hwRes = (HttpWebResponse)hwRq.GetResponse();
     smRespStream = hwRes.GetResponseStream();
     iFileSize = hwRes.ContentLength;
     int iByteSize;
     byte[] downBuffer = new byte[iBufferSize];
     while ((iByteSize = smRespStream.Read(downBuffer, 0, downBuffer.Length)) > 0)
         saveFileStream.Write(downBuffer, 0, iByteSize);
     saveFileStream.Close();
 }