title: How to shutdown TPL Dataflow on fatal exception, in a gracefully way?
body: <p>I am using a sequential pipeline build on TPL Dataflow, that consists in 3 blocks:</p>
  
  <ul>
  <li>B1 - prepares the message</li>
  <li>B2 - posts the message to a remote service</li>
  <li>B3 - saves the result</li>
  </ul>
  
  <p>The problem is how to shutdown the pipeline, when an error like service down occurs. The pipeline  must go down in a controlled manner, so no results from B2 are lost.</p>