these 4 derivations will be built:
  /nix/store/z42pn3n3ldd6ww8axakcdw371jprz2k1-Cargo.toml.drv
  /nix/store/6w3pxjlvb1rh32kb8w5vqw4nyhnx3mqn-source.drv
  /nix/store/m8g3mivbs40fa5jv6bamajpdfw7bwfbp-harmonia-deps-3.2.0.drv
  /nix/store/6fgc69fpkwd2m70p6k7rarg6sq9y0hpv-harmonia-3.2.0.drv