these 4 derivations will be built:
  /nix/store/740465pji8glkglw9x5s449wsipv1qd0-Cargo.toml.drv
  /nix/store/xxirs8i6q7mx1n3mnia59rm29pv7m973-source.drv
  /nix/store/7ab9ga323mjw1xs7c82jwavrbsihf95z-harmonia-deps-3.2.0.drv
  /nix/store/m8zcksjpyrly5r6a7vawg6gh7ip8m67k-harmonia-3.2.0.drv