Flink Table API in Kotlin states the supplier statistics as a declarative windowed aggregation over a DataStream, with late rows routed by hand.

Flink DataStream API in Kotlin computes the same supplier statistics, using watermarks for event time and side outputs to collect late order events.

Kafka Streams in Kotlin aggregates Avro order events into tumbling window supplier statistics and handles late records with a custom extractor.

Avro and Schema Registry replace hand written JSON codecs in a Kotlin Kafka producer and consumer, with generated classes and graceful shutdown.

A Kotlin Kafka producer and consumer for order events, with custom JSON serialisers, admin helpers and a Gradle build, run on Factor House Local.