anchor.diff:          mapAttrsToList (_: args: register-hostname {
            zone = args.name;
            inherit (args) zoneId iamCredentialName useLocalHostname;
  -       }) config.ec2.route53RegisterHostname)} | ${xargs} -n1 -P6 ${bash}
  +       }) config.ec2.route53RegisterHostname)} | ${xargs} -n1 -P2 ${bash}
   
       ${optionalString (!config.ec2.metadata) ''
       ip route add blackhole 169.254.169.254/32
  
positive.code:     hostname=$(${hostname}).${zone}
      record_value=$(${wget} http://169.254.169.254/latest/meta-data/${query})
  
      ${curl-nofail} -d @/dev/stdin \
            -H "Content-Type: text/xml" \
            -H "x-amz-date: $date" \
            -H "$auth_header" \
  
negative.code: let
    inherit (lib) concatStringsSep mapAttrsToList mkOverride mkOption types optionalString;
  
    plat-pkgs = import <platform/pkgs> { inherit pkgs; };
    retry = "${plat-pkgs.retry}/bin/retry";
    base64 = "${pkgs.coreutils}/bin/base64";
    jq = "/usr/bin/env LD_LIBRARY_PATH=${pkgs.jq}/lib ${pkgs.jq}/bin/jq";
    curl = "${pkgs.curl}/bin/curl -s --retry 3 --retry-delay 0 --fail";
  