these 4 derivations will be built:
  /nix/store/cc5jsp7p8af52r51dmcpb16xy1l43kzh-Cargo.toml.drv
  /nix/store/1gdf141vjx5myz73f9h7mys028pkbjwp-source.drv
  /nix/store/r32pcx7jd0pms0r0zzc22nn03k5w9ld3-harmonia-deps-3.2.0.drv
  /nix/store/5m8m32j9v69qxlwmc1l0qlhpi8iy06y4-harmonia-3.2.0.drv