I just realized that I forgot to publish my presentation from this year's GUADEC. Sorry, here it is!

You can also get the ODP file for the presentation. This is released under a CC-BY-SA license.

This is the video of the presentation.

Update Dec/06: Keen readers spotted an incorrect use of opaque pointers; I've updated the example code in the presentation to match Jordan's fix with the recommended usage. That merge request has an interesting conversation on FFI esoterica, too.