anchor.diff:        ControlPath ${cfg.controlPath}
         ControlPersist ${cfg.controlPersist}
   
  +      ${cfg.extraConfig}
  +
         ${concatStringsSep "\n\n" (
           map matchBlockStr (
           builtins.attrValues cfg.matchBlocks))}
  
positive.code:          "  ServerAliveInterval ${toString cf.serverAliveInterval}"
      ++ optional (!cf.checkHostIP)         "  CheckHostIP no"
      ++ optional (cf.proxyCommand != null) "  ProxyCommand ${cf.proxyCommand}"
    );
  
  in
  
negative.code:       example = "10m";
        description = ''
          Whether control socket should remain open in the background.
        '';
      };
  
      extraConfig = mkOption {
        type = types.lines;
        default = "";
        description = ''
          Extra configuration.
        '';
      };
  
  