structuredAttrs is enabled

trying https://hackage.haskell.org/package/nix-diff-1.0.21.tar.gz
  % Total    % Received % Xferd  Average Speed  Time    Time    Time   Current
                                 Dload  Upload  Total   Spent   Left   Speed
  0      0   0      0   0      0      0      0                              0
100  20285 100  20285   0      0  37025      0                              0