title: Spring Cloud Data Flow aggregator example
body: <p>Can anybody point to some examples specific to String Cloud Data Flow (not Stream XD) on how to write splitters and aggregators? </p>
  
  <p>In particular non trivial splitting and joining of messages. Any non trivial example of complex streams. How do you define a stream that is aggregating messages after spliting, how about when there are Routers and diferent processing for the produced messages, how is all that aggregated later?</p>
  
  <p>PS: Sorry for the long question, I will clarify as needed.
  thanks!</p>