title: Combine two streams in Apache Flink regardless on window time
body: <p>I have two data streams that I want to combine. The problem is that one data stream has a much higher frequency than the other and there are times where one stream is not receiving events at all. Is it possible to use the last event from the one stream and join it with the other stream on every event that is coming?</p>
  <p>The only solution I found is using the join function, but you have to specify a common window, where you can apply the join function. This is window is not reached, when one stream is not receiving any events.</p>
  <p>Is there a possibility to apply the join function on every event that is coming from either one stream or the other and maintain state of the last consumed event and use this event for the join function?</p>