HttpWebRequest.BeginGetResponse method

Hello.
I have carefully read the code example at https://video2.skills-academy.com/ru-ru/dotnet/api/system.net.httpwebrequest.begingetresponse?view=net-5.0#-----------
and tried to run it. It worked fine, but i wanted to test TimeoutCallback (when timedout == true) by decreasing DefaultTimeout to 500 ms. And i got 2 exceptions:

1. after request.Abort(); starts RespCallback method and line
   myRequestState.response = (HttpWebResponse) myHttpWebRequest.EndGetResponse(asynchronousResult);
   throws exception (Status:RequestCanceled);
2. in Main method: line
   myRequestState.response.Close();
   throws null-reference-exception (myRequestState.response is null).
   Maybe it makes sense to improve the code?
   Did I fix it optimally next way?
3. private static void RespCallback(IAsyncResult asynchronousResult)
   {
   if (((Task<WebResponse>)asynchronousResult).Status != TaskStatus.Canceled)
   try...
4. in Main()
   // Release the HttpWebResponse resource.
   if (myRequestState.response != null)
   myRequestState.response.Close();
   Or can you suggest a better solution?
   Thanks