these 4 derivations will be built:
  /nix/store/cp1wbcaxzyi9xxnmvj3s8vc6fra3yvhm-Cargo.toml.drv
  /nix/store/xfwmpyr8xs5g9s0abws8x08lrm6sfkw7-source.drv
  /nix/store/n0mjikpn8wad5y257yv91z9yb8zhvn79-harmonia-deps-3.3.0.drv
  /nix/store/gbbcvjhz8h9cw74qb51r0d1xrmmdgkbl-harmonia-3.3.0.drv