public static IEnumerable <BlockViewOnAsyncLongOperationMessageObserver> BuildObservers(ViewGroup fromViewGroup)
        {
            var viewsToBlock = new List <View>();

            fromViewGroup.ForEachView <View>(view =>
            {
                viewsToBlock.Add(view);
            });

            return
                (viewsToBlock.Select(
                     view => new BlockViewOnAsyncLongOperationMessageObserver(new WeakReference <View>(view))));
        }