title: AWS IOT analytics to trigger event when attribute changes state
body: <p>Is it possible to detect if an attribute of an iOT message changed say from false to true and trigger an action?  I would like to capture all status changes.
  I'm wondering if iot analytics is the right tool for this.
  Going through the tutorial it appears that choosing a delta time window and querying the data could trigger an event.
  The smaller the time window would be the more real time my alarm would be. One problem I see with this is that alarm would be repeatedly triggered.<br>
  Is this in the right direction?  </p>