Sorry I missed that, I scanned your readme and because I didn't see "code actions" or similar I presumed it wasn't there.

Anyways I've just tested and it works perfectly! I used the default config with no modification.

 

I'm on arm64 linux under macOS and haven't found the corresponding dart binaries

This is probably an issue worth raising to the Dart/Flutter teams, ARM is slowly beginning to proliferate the desktop market so they'll have to consider offering these binaries.