Error when accessing the group's name in ALAssetsGroup property.

Group Name in ALAssetsGroup

ALAssetsLibrary library;
protected List<ALAsset> assets = new List<ALAsset>();

public override void ViewDidLoad ()
{
	base.ViewDidLoad ();
			
	library = new ALAssetsLibrary();
			
	library.Enumerate(ALAssetsGroupType.All, AssetGroupEnumerator, (error) => { 
		Debug.WriteLine("Failure {0}", error.LocalizedDescription);
	});
			
}
		
void AssetGroupEnumerator(ALAssetsGroup group, ref bool stop) 
{
	if(group != null)
	{
		Console.WriteLine("Assets in {0} is {1}", group.Name ?? "group" , group.Count);
		//group.Enumerate(AssetEnumerator);
	}
}