these 2 derivations will be built:
  /nix/store/ddsdwyc2jq2w23bj72q791lqn47wynsq-devshell-dir.drv
  /nix/store/qh6pz5sajwb49bf923c2r1gyl0nxhqdk-devshell.drv
this path will be fetched (222.1 MiB download, 634.9 MiB unpacked):
  /nix/store/9mckxfn8npw4mrrkyp2m0vp8y76qp0n4-dart-3.13.0