I decided to start sharing parts of #fediQuest as they become mature.
Today, I am releasing a #Golang library for decoding ActivityStreams 2.0 objects into native Go objects and also for encoding Go objects into ActivityStreams 2.0 JSON objects.
Repo: https://github.com/MatejLach/astreams
The usage is your typical Go Marshal/Unmarshal, (see tests for examples).
The license is copyleft (AGPLv3).
Your feedback (and a star) are welcome :-)