[Nix-dev] Binary cache substituter

[Michael Raskin]

>For instance, if you add the line
>
>  binary-caches = http://nixos.org/binary-cache

Great! Thanks.

>* The main downside to the binary cache substituter is that it has no support
>for binary patches (and it's not obvious how to support them).  If you really
>need them, you can add "force-manifest = true" to nix.conf to force nix-channel
>to nix-pull the channel's manifest.

Are binary diffs pregenerated - and only for a fixed set of second 
arguments?

If yes, narinfo could contain them. 

If no, you could send list of hashes of existing paths with the same 
name (or name minus version) to server and the server will tell you if
you get any binary diffs.