anchor.diff:  
           unitConfig.ConditionPathExists = [ configDir stateDir ];
   
  +        restartTriggers = [ config.environment.etc."hqplayer/hqplayerd.xml".source ];
  +
           preStart = ''
             cp -r "${pkg}/var/lib/hqplayer/web" "${stateDir}"
             chmod -R u+wX "${stateDir}/web"
  
positive.code: 
      environment = {
        etc = {
          "hqplayer/hqplayerd4-key.xml" = mkIf (cfg.licenseFile != null) { source = cfg.licenseFile; };
          "modules-load.d/taudio2.conf".source = "${pkg}/etc/modules-load.d/taudio2.conf";
        };
  
negative.code:           Opens ports needed for the WebUI and controller API.
          '';
        };
  
        config = mkOption {
          type = types.nullOr types.lines;
          default = null;
          description = ''
            HQplayer daemon configuration, written to /etc/hqplayer/hqplayerd.xml.
  
            Refer to ${pkg}/share/doc/hqplayerd/readme.txt for possible values.
          '';
        };
      };
    };
  
  