these 4 derivations will be built:
  /nix/store/3ghplnp3gfkgf2bm2l1mknl0lfw00cs6-Cargo.toml.drv
  /nix/store/9qx8w83yjlsgvis7qibjl7yqdqdgx2zk-source.drv
  /nix/store/rrxx30dh9r6zjw74aifmh4i65cfdfh4w-harmonia-deps-3.2.0.drv
  /nix/store/bd8r2i8s1z5wxizzxsh1pb4l17w3dy5x-harmonia-3.2.0.drv