Hi, I have a pipeline that do fixed windows and then it create a KV and then GroupByKey the all this is fine and then I do a Combine.groupedValues with a my own Combine.CombineFn and the the two last steps is a MapElements.via() my a SimpleFunction that crates a JSON string and the last step is a PubsubIO.writeStrings().to() and every thing looks find in the IDE but then when I try to run it I get `Exception in thread "main" java.lang.NullPointerException: Outputs for non-root node 1m_CalculatePageViews/1m_format_pageviews are null`Anyone have any ideas around what I have missed in my pipeline design?
dennis [4:02 PM] where the 1m_format_pageviews is the MapElements.via() that create json
