Decorate_events in Logstash 5 kafka input

Was this setting removed? I can't seem to find it in the documentation and it causes a config error when used.
I have a Kafka -> Logstash ->Elasticsearch setup and I would like to set the ES index according to the Kafka topic. How can I achieve this without decorate_events?


It needs to be ported, see here: Pulling topic metadata from kafka 0.9