anchor.diff:       Future.wait([
          Future.wait(clientSockets.map((s) => s.close())),
          serverSocket.close()
  -     ]).then((_) => _done.complete());
  +     ]);
   
   }
  
positive.code:   List<Socket> clientSockets = [];
    Map<String, List<Map> > requestors = {};
    Map<String, Map> currentLock = {};
    Completer _done;
  
    Future get closed => _done.future;
  
    Locker.config(this.serverSocket);
  
  
negative.code:         .then((ServerSocket sSocket) {
            Locker locker = new Locker.config(sSocket);
            locker.serverSocket.listen(locker.handleClient);
            return locker;
          });
  
  