public Future<Boolean> addAsync(final V value) {
   final Promise<Boolean> promise = new DefaultPromise<Boolean>() {};
   GlobalEventExecutor.INSTANCE.execute(
       new Runnable() {
         @Override
         public void run() {
           try {
             boolean res = add(value);
             promise.setSuccess(res);
           } catch (Exception e) {
             promise.setFailure(e);
           }
         }
       });
   return promise;
 }