these 4 derivations will be built:
  /nix/store/zvyzwbjxx8vf3p1jzgcp9sca1q88y236-Cargo.toml.drv
  /nix/store/cckkzfwmcwiz3fr2n7dk7ggbdbixrqdi-source.drv
  /nix/store/9hhd5ss7gykxmax326hw2am8hslb7q90-harmonia-deps-3.1.0.drv
  /nix/store/axb4dn363f6lh94znspc86l6mnkrvpb5-harmonia-3.1.0.drv