these 4 derivations will be built:
  /nix/store/wwlm2ijxn907w95p0ri5gdprv8ffwm2n-Cargo.toml.drv
  /nix/store/9wvkcpi2pnc9pbrrwaycdfvvcmqgxg0g-source.drv
  /nix/store/w0xr7wbd0gyjpvp1093d7jwr8799h4xn-harmonia-deps-3.2.0.drv
  /nix/store/lm18cczch0z9hxrj9vln57q19hxv35sq-harmonia-llvm-cov-3.2.0.drv