nix run nix-darwin -- switch --refresh --flake github:r33drichards/darwin
nix run nix-darwin -- switch --refresh --flake .
sudo nix --extra-experimental-features 'nix-command flakes'  run nix-darwin -- switch  --refresh --flake .#rws-MacBook-Air                     

brew tap cfergeau/crc
brew install vfkit

configure git auth

1. create a personal access token

2. configure nix.conf to use the token

mkdir -p ~/.config/nix
touch ~/.config/nix/nix.conf
echo "access-tokens = github.com=" >> ~/.config/nix/nix.conf