title: Uploading large Files with HttpWebRequest (AllowWriteSteamBuffering doesnt solve this)
body: <p>My problem is the following:
  I am currently extensively testing my application and now I got to know that it isn't able to handle uploads of large files. Of course I informed myself of this problem, and the <code>AllowWriteStreamBuffering</code>-Property is already set to false, but when I try to upload a file with a size of ~ 700 Mb, my PC freezes (I have 4 Gb RAM and I don't get an <code>MemoryOutOfRangeException</code>). Neither I am able to use the <code>HttpClient</code>-Class because I have to provide support for .NET Framework 4, nor I can chunk the upload because the target-servers do not support that kind of upload.
  I think the memory problem is caused because the data I already sent (while uploading) is still allocated in the RAM.
  These lines of code are responsible for that:</p>
  
  <pre><code>while ((bytesRead = fileStream.Read(fileBuffer, 0, fileBuffer.Length)) != 0)
  {
      requestStream.Write(fileBuffer, 0, (int)bytesRead);
  }
  </code></pre>
  
  <p>How can I delete the data which is already sent but still using my memory?
  If this isn't the cause of the problem, how can I solve it then?</p>