I believe this is a typo

[posix4e]

How did you test this example?

[mallocator]

Indeed this was a typo.

I tested the plugin by using it (it's currently running on our development cluster). The import.sh script provided was copied from the elasticsearch-mysql-river (which is also currently being used).
The script we use to set up our river actually looks a lot different by now, and instead of making sure that I didn't publish any sensitive data, it was safer to just copy the sample from the MySQL project.

Thanks for correcting the mistake. I hope nobody else had problems with that.