these 2 derivations will be built:
  /nix/store/bdx5d6n07dhccnqs0fq19pyvshqyz6kp-devshell-dir.drv
  /nix/store/nm4sw53590qb2wa6n1hahf9fmwf667l3-devshell.drv
this path will be fetched (222.2 MiB download, 634.8 MiB unpacked):
  /nix/store/2x1b3jkwhkg52xa5bnqrc7n04vz23n3b-dart-3.13.0