these 4 derivations will be built:
  /nix/store/fk74qkxgly1148caawlg8s60hsjgqiq5-Cargo.toml.drv
  /nix/store/y5b0brnprg1v17d8fhzy5rwhi6555p12-source.drv
  /nix/store/rvmzqwpi5s32k59yd8g9j0vvd7gmriwc-iets-deps-0.1.0.drv
  /nix/store/cyvvnik07xypnr5smx0ifzn6y45cz77x-iets-doc-0.1.0.drv