anchor.diff:  let
   
     cfg = config.systemd.network;
  -
  -  waitOnline = config.networking.waitForOnline;
   
     checkLink = checkUnitConfig "Link" [
       (assertOnlyFields [
  
positive.code:       restartTriggers = map (f: f.source) (unitFiles);
      };
  
      systemd.services.systemd-networkd-wait-online = lib.mkIf waitOnline {
        wantedBy = [ "network-online.target" ];
      };
  
      systemd.services."systemd-network-wait-online@" = lib.mkIf waitOnline {
        description = "Wait for Network Interface %I to be Configured";
        conflicts = [ "shutdown.target" ];
        requisite = [ "systemd-networkd.service" ];
  
negative.code:   config = mkIf config.systemd.network.enable {
  
      systemd.additionalUpstreamSystemUnits = [
        "systemd-networkd.service" "systemd-networkd-wait-online.service"
        "org.freedesktop.network1.busname"
      ];
  
      systemd.network.units = mapAttrs' (n: v: nameValuePair "${n}.link" (linkToUnit n v)) cfg.links
        // mapAttrs' (n: v: nameValuePair "${n}.netdev" (netdevToUnit n v)) cfg.netdevs
  