Disclaimer: I&#x27;m the author of the post.<p>In this particular example, both events (item_reported and item_deleted) end up in destructive actions identified by unique id. That idempotency makes safe working with Kafka&#x27;s at-least-once semantics. You can see that it&#x27;s safe to execute several times this line of code:<p><pre><code>  val newItemsToBeDeleted = items.filterNot(_ == item)</code></pre>