Enhance kafka commit

[pdepaepe]

Hello,

I think, it could be very useful to enhance "Kafka output" with a kind of timer option and associate it with the actual kafka_coalesce parameter.

kafka_coalesce=100
kafka_flush_interval=5s

If one of theses conditions is met, commit the batch to Kafka.

Thanks

[crisidev]

We restarted active development of Flowgger recently. I am not very familiar with Kafka, is this something still needed?