added cargo files

PinePods-0.8.2/mobile/lib/services/download/download_service.dart

@@ -0,0 +1,13 @@
+// Copyright 2020 Ben Hills and the project contributors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:pinepods_mobile/entities/episode.dart';
+
+abstract class DownloadService {
+  Future<bool> downloadEpisode(Episode episode);
+
+  Future<Episode?> findEpisodeByTaskId(String taskId);
+
+  void dispose();
+}