How to get kafka partition ID?

[Yuta Morisawa]

Hi

I want to apply a window function simply on data from each 
kafka-partition(I mean I don't need any grouping and just want to 
process data parallely).
I think the best way to do so is drawing kafka partition id and use it 
for keyBy function.
For example,
val data = stream.keyBy(kafka-partitionID)
                 .window(...)
                 .fold(...)

But, I could not find the way.
How can I get the kafka-partition ID in Flink code?


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Regards,
Yuta