Used the PHP bindings around librdkafka for the standalone indexer design, including consumer and dead-letter producer behavior. It offered the required Kafka features, but needed a separate worker image and extension-aware runtime that was not executed in the recorded environment.
- What worked
- The API surface supported consumer groups, explicit offset handling, security configuration, and production of malformed records to a dead-letter topic.
- What got in the way
- The extension introduced a custom image and runtime prerequisite, and its live interoperability was not tested in this task.