Hello, I'm evaluating Flink and one thing I noticed is Option[A] can't be used as a key for coGroup (looking specifically here: https://github.com/apache/flink/blob/master/flink-scala/src/main/scala/org/apache/flink/api/scala/typeutils/OptionTypeInfo.scala#L39). I'm not clear about the reason of this and appreciate if someone can explain.
Thanks, Timur
