private TransformingBackendAccess(
     IBackendAccess <TModel> modelBackendAccess,
     Func <TModel[], TViewModel[]> transformingPageFactory,
     Func <TModel, TViewModel> transformingPlaceholderFactory)
 {
     _modelBackendAccess             = modelBackendAccess;
     _transformingPageFactory        = transformingPageFactory;
     _transformingPlaceholderFactory = transformingPlaceholderFactory;
 }
 internal static IBackendAccess <TViewModel> CreateTransformingBackendAccess(
     IBackendAccess <TModel> modelBackendAccess,
     Func <TModel[], TViewModel[]> transformingPageFactory,
     Func <TModel, TViewModel> transformingPlaceholderFactory)
 {
     return(new TransformingBackendAccess <TModel, TViewModel>(
                modelBackendAccess,
                transformingPageFactory,
                transformingPlaceholderFactory));
 }