these 4 derivations will be built:
  /nix/store/qjal4cihj82jp3gnv4ip76kg5rhbbk7j-crate-rand-0.10.3.tar.gz.drv
  /nix/store/y2ws3avrjsfyj96rhni9kgimbk642syc-rand-0.10.3.drv
  /nix/store/2czvhva10b6yqzfddb2qpwji5qqimjsm-cargo-vendor-dir.drv
  /nix/store/pk831p4jlvby88pvnvblbfkx9q68vhbj-fast-nix-gc-proptest-0.1.0.drv
this path will be fetched (2.4 KiB download, 8.2 KiB unpacked):
  /nix/store/5qfpy9g021x1r5326mw203al37qh091i-mirrors-list