anchor.diff:  let
   
     cfg = config.services.bind;
  +
  +  bindPkg = config.services.bind.package;
   
     bindUser = "named";
   
  
positive.code:       preStart = ''
          mkdir -m 0755 -p /etc/bind
          if ! [ -f "/etc/bind/rndc.key" ]; then
            ${pkgs.bind.out}/sbin/rndc-confgen -c /etc/bind/rndc.key -u ${bindUser} -a -A hmac-sha256 2>/dev/null
          fi
  
          ${pkgs.coreutils}/bin/mkdir -p /run/named
  
negative.code:       '';
  
        serviceConfig = {
          ExecStart = "${bindPkg.out}/sbin/named -u ${bindUser} ${optionalString cfg.ipv4Only "-4"} -c ${cfg.configFile} -f";
          ExecReload = "${bindPkg.out}/sbin/rndc -k '/etc/bind/rndc.key' reload";
          ExecStop = "${bindPkg.out}/sbin/rndc -k '/etc/bind/rndc.key' stop";
        };
  
        unitConfig.Documentation = "man:named(8)";
  