public async Task <bool> DeleteItemAsync(int index)
{
using (var doc = _db.GetDocument(CoreApp.DocId))
using (var mdoc = doc.ToMutable())
using (MutableArrayObject listItems = mdoc.GetArray(CoreApp.ArrKey)) {
listItems.RemoveAt(index);
_db.Save(mdoc);
}
_items.Remove(index);
return(await Task.FromResult(true));
}