ITotalCountProvider casting error

hello, i have a C#/XAML project that we are moving over to Xamarin. One of the tasks is to fetch a set of pictures from Azure Mobile Services. It seems that there is uneven support across enumerable collections to determine Count. Any tips or hints on how i can get around the casting error to derive TotalCount of records being returned?

<code>
        var query = picturesTable.OrderBy (x => x.CaptureTimeStamp).IncludeTotalCount ();
        var results = query.ToEnumerableAsync ();
        long count = ((ITotalCountProvider)results).TotalCount;
 </code>

thank you in advance.

Ankur