There's a few things missing in the steps which I'd like to highlight as might help others, they are below:-
1. I needed to have the librdkafka dlls present in the bin folder to get it working, else I kept getting a runtime exception complaining that it couldn't find the dll. To get it I launched the extensions.csproj and installed the nuget package (https://www.nuget.org/packages/librdkafka.redist/) . This then gave me access to the dlls, which I copied into the bin folder of the functionApp. It then worked fine!
2. Also a small tweak to the readme, you need to add --package to it.
$ func extensions install --package Microsoft.Azure.WebJobs.Extensions.Kafka --version 2.0.0-beta
3. I also renamed the local in pom.xml to something else to get rid of the warning.
<repository>
<id>extensions</id>
<url>file://${project.basedir}/src/repo</url>
</repository>
Is there any specific timeline when this might move from Preview to a stable version? Thanks, Fatima.