these 4 derivations will be built:
  /nix/store/7894nxcs6ymv2sh6m4fbrvbdqk4v5c8v-Cargo.toml.drv
  /nix/store/6g5r3yvr079xcnfy3wxphcvdqvvs3sk0-source.drv
  /nix/store/v9v8plyyxmm6incxhgfss1g402pqk5p8-harmonia-deps-3.3.0.drv
  /nix/store/a1xcpaim4fqxkfwnw1dqyn9k9x1rig4z-harmonia-3.3.0.drv