title: What thread calls the completed event handler on silverlight WCF calls?
body: <p>Assume that I have Silverlight app doing a call to a WCF service:</p>
  
  <pre><code>void DoStuff()
  {
      MyProxy proxy = new MyProxy();
      proxy.DoStuffCompleted += DoStuffCompleted;
      proxy.DoStuffAsync();
  }
  
  void DoStuffCompleted(object sender, DoStuffCompletedEventArgs e)
  {
      // Handle the result.
  }
  </code></pre>
  
  <p><code>DoStuff</code> is called by the UI thread. What thread will eventually call the <code>DoStuffCompleted</code> method? If I invoke two async calls at the same time, is there a possibility that both the completed events are fired simultaneously, on different threads?</p>