this derivation will be built:
  /nix/store/cfhhs543b3ki4nhwfnpjkp1d6h9xbm58-nix-shell.drv
this path will be fetched (1.4 MiB download, 3.6 MiB unpacked):
  /nix/store/hihsfr2bvvpx619c5q4rfc18p2bbxxiw-cargo-llvm-cov-0.9.0