title: WaWorkerHost.exe crashes role: CallbackException
body: <p>When I run my WorkerRole C# application on Azure, after a while waworkerhost.exe crashes due the following exception:</p>
  
  <pre><code>Application: WaWorkerHost.exe
  Framework Version: v4.0.30319
  Description: The process was terminated due to an unhandled exception.
  Exception Info: System.Runtime.CallbackException
  Stack:
     at System.Runtime.Fx+IOCompletionThunk.UnhandledExceptionFrame(UInt32, UInt32, System.Threading.NativeOverlapped*)
     at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32, UInt32, System.Threading.NativeOverlapped*)
  </code></pre>
  
  <p>I have an application that generates load to a webserver. I don't care about the actual response, but i want to control the number of requests made per second.
  Therefore i have a Timer that fires every second and generates a number of requests. I have tried the following options:</p>
  
  <ul>
  <li>Parallel.For with WebRequests</li>
  <li>For loop with ASync WebRequests </li>
  <li>For loop with ThreadPool.QueueUserWorkItem(do
  webrequest)</li>
  </ul>
  
  <p>When the number of requests increase, the exception occurs (8+ req/sec). The same exception for all three options. When I run the role in local DevelopmentFabric all three options work just fine. If someone could give me some pointers on what might be going wrong I appreciate it. If you have other ideas to generate this type of load from Azure and C#, please share your thoughts. </p>