title: Which exception is throw by URLFetchService for timeouts?
body: <p>The Google App Engine UrlFetchService has a setDeadline FetchOption which is suppose to raise an exception when tripped. </p>
  
  <blockquote>
    <p>The app can specify the maximum amount of time to wait when it makes the call. If the maximum wait time is exceeded, the call raises an exception.</p>
  </blockquote>
  
  <p>Which Exception?</p>
  
  <p>If it is an IOException, how should I discriminate between a deadline timeout and other causes?</p>