these 4 derivations will be built:
  /nix/store/4dp0hrhg08c758l6z4gim99n8k6cy1fb-Cargo.toml.drv
  /nix/store/ckbwr5ngj167hbhkmpvdyx0kgicqn8mi-source.drv
  /nix/store/5k94q6a79k1piyv0ls58zdqhgqmhpr51-harmonia-deps-3.3.0.drv
  /nix/store/pnnfscqikrpxdf6ih0x4ahvspjiy0a4l-harmonia-3.3.0.drv