these 3 derivations will be built:
  /nix/store/ikf6xwafijqxnmzgfazdc597nmjmb6m8-serde_json-1.0.154.drv
  /nix/store/80fcm3s62yli5mc9f6gx7nifz1qha011-cargo-vendor-dir.drv
  /nix/store/4gq7lki662ama74v0sqh6pahb2cdf0wk-bob-0.1.0.drv