these 4 derivations will be built:
  /nix/store/g704hhdawhcrzn18614hk3gzbk7ms60d-Cargo.toml.drv
  /nix/store/mrdb4spnmpdb5g9hj53hzv27yf0pp2ca-source.drv
  /nix/store/41brm904k96lsfypcax8yxnb6cn0cs7h-herdr-eternal-deps-0.1.0.drv
  /nix/store/8g280mb5nfdmcarka2i19jnj2qxhfg9a-herdr-eternal-0.1.0.drv