File picker not working iPad

I'm using Xamarin.Plugin.FilePicker in MvvmCross."https://github.com/Studyxnet/FilePicker-Plugin-for-Xamarin-and-Windows" for the browser "var pickedFile = await CrossFilePicker.Current.PickFile();" getting null value from pickerfile.
it's working fine in iPhone but not working in iPad. can you please anyone suggest, what's the problem.
please share any other dll.