these 2 derivations will be built:
  /nix/store/y9mca7dcbzwrwdz94jnl4f64q8v8zrpj-cargo-vendor-dir.drv
  /nix/store/mpdx6n22qq43jz0hw3lbfzx47rlsp56b-ssync-0.17.0.drv