Hi all, I have a couple questions about FoldFunction and WindowFunction:
1. When using a RichFoldFunction after a window as in keyedStream.window().fold(new RichFoldFunction()), is the close() method called after each window or after all the windows for that key are fired? 2. When applying a FoldFunction to a window followed by a WindowFunction via apply <https://ci.apache.org/projects/flink/flink-docs-master/api/java/org/apache/flink/streaming/api/datastream/WindowedStream.html#apply-R-org.apache.flink.api.common.functions.FoldFunction-org.apache.flink.streaming.api.functions.windowing.WindowFunction->(R initialValue, FoldFunction <https://ci.apache.org/projects/flink/flink-docs-master/api/java/org/apache/flink/api/common/functions/FoldFunction.html> <T <https://ci.apache.org/projects/flink/flink-docs-master/api/java/org/apache/flink/streaming/api/datastream/WindowedStream.html>,R> foldFunction, WindowFunction <https://ci.apache.org/projects/flink/flink-docs-master/api/java/org/apache/flink/streaming/api/functions/windowing/WindowFunction.html> <R,R,K <https://ci.apache.org/projects/flink/flink-docs-master/api/java/org/apache/flink/streaming/api/datastream/WindowedStream.html> ,W <https://ci.apache.org/projects/flink/flink-docs-master/api/java/org/apache/flink/streaming/api/datastream/WindowedStream.html> > function), why should the output of the WindowFunction be of the same type as the input? It would be practical to have a different output type sometimes, for example one would fold tuples in the FoldFunction and then process the (only) aggregated tuple in the Window function and emit an Integer. Best, Yassine
