The Kafka version of salobj uses aiokafka, which is based on kafka_python. Unfortunately kafka_python appears to be moribund; there have been no new releases for almost 2 years.

Switch to confluent_kafka, since it is maintained and the company claims it will continue to be. The API is not as nice, but it's good enough. Two other advantages are:

• salobj kafka already uses confluent_kafka for some things, because aiokafka is missing some needed APIs.
• confluent_kafka is designed to be high performance, so we might see a small speed increase (and are very unlikely to lose speed).

I did already test confluent_kafka for salobj, so I don't expect this to be a big job. Nonetheless I am leaving time to rerun the performance tests.