First of all thanks for this awesome project!

Wanted to ask what would be necessary to add support for the Arduino SAMD21 based boards (specifically the MKR Zero)? Is there maybe already someone working on this?

The only relevant issues/PRs I could find are #4863 and #4994 but whilst they add SAMD support they don't contain anything for the Arduino boards.

Whilst I have no experience with this I could work on creating a PR to add it myself, but I could use some help/input on what needs to be done to add support for a new board. I couldn't really find any documentation for it.