these 4 derivations will be built:
  /nix/store/cka4bh50mi6xziai9249jciqcp66fgl8-Cargo.toml.drv
  /nix/store/r6lz5dhyxbrspw3nnnq03pskx7wsx40n-source.drv
  /nix/store/grcl49api9wdsvg8myly56fcpsb8m49v-harmonia-deps-3.2.0.drv
  /nix/store/gm3ccmg0n0cw085fsx6w9zpsq5smxhk4-harmonia-3.2.0.drv