public static void DeleteDocById(string id)
        {
            // Get the doc first
            var indexClient = GetSearchIndexClient();

            SearchDocument document = indexClient.Documents.Get <SearchDocument>(id);

            if (document != null)
            {
                // Remove file from azure
                AzureStorageHelper.DeleteBlob(document.DocFileName);

                // Now remove from index
                var batch = IndexBatch.Delete(new[] { document });
                PerformIndexOperation(batch);
            }
        }