Assumes as inputs a BroadcastStream and a DataStream or
KeyedStream and applies the given BroadcastProcessFunction or
KeyedBroadcastProcessFunction on them, thereby creating a transformed output
func – The BroadcastProcessFunction that is called for each element in the
non-broadcasted DataStream, or the KeyedBroadcastProcessFunction that
is called for each element in the non-broadcasted KeyedStream.
output_type – The type of the output elements, should be
common.TypeInformation or list (implicit RowTypeInfo) or None (