Hi I have been trying out the apache beam go SDK for running aggregation on logs from kafka. I have been trying to write a kafka reader using ParDoFns and aggregating the result using WindowInto and GroupByKey. However the `GroupByKey`'s output only outputs result if I finish my kafka message outputs. I am using the direct runner for testing these out. It seems like a bug in the runner/GroupByKey implementation as it seems to assume that the output is going to exhaust even in the case of windowed input.
Pipeline representation: impulse -> kafka consumption ParDo(consumes kafka messages in a loop and emits metric with beam.EventTime) -> add timestamp ParDo -> WindowInto(fixed windows) -> Add window max Timestamp as key Pardo -> *GroupByKey* The *GroupByKey *gets stuck until first kafka consumption pardo exits. This doesn't seem desired. I haven't been unable to pinpoint the exact line of code why this gets stuck. Can someone help me out with this. Thanks for your help. Best Anand Singh Kunwar
