these 4 derivations will be built:
  /nix/store/291v843v3g4pn3hviwy2pzrz2swfbfx0-Cargo.toml.drv
  /nix/store/hvnmafhbbhxmszxhi7zbpg9iqdn3xaf3-source.drv
  /nix/store/1gmfz86v6g7m2pgl8rrcb8nm0h7gvikp-harmonia-deps-3.2.0.drv
  /nix/store/10spzsdnizqpx44g3mw8mvjkk3m5c8dc-harmonia-3.2.0.drv