title: Flink - what is the difference between an operator that forwards to a DiscardingSink vs sending nowhere?
body: <p>I have a Dataflow in Flink as follows:</p>
  <p>Source -&gt; Operator -&gt; DiscardingSink</p>
  <p>Is there any difference between that and one that has no Sink?</p>
  <p>Source -&gt; Operator -&gt;</p>
  <p>From my tests it seems to run the same, although in the first case I see that the operator and sink are chained and no records are sent from the sink. In the second case I can see that records are forwarded, but they have nowhere to go.</p>
  <p>From my understanding the Operator will be filling up it's outgoing network buffers with records, and I would expect at some point to see back pressure, but that doesn't happen, so what are the semantics I should expect here?</p>