Reorganize code to prepare for more features. (#227)

pkgs/memory_usage/lib/DEPENDENCIES.md

@@ -1,10 +1,15 @@
 <!---
 Generated by https://github.com/polina-c/layerlens
-Dependencies that create loop are markes with `!`.
+Dependencies that create loops (inversions) are marked with `!`.
 -->
 
 ```mermaid
 flowchart TD;
 memory_usage.dart-->src;
 ```
 
+### Inversions
+In this folder: 0
+
+Including sub-folders: 0
+

pkgs/memory_usage/lib/memory_usage.dart

@@ -2,5 +2,5 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-export 'src/model.dart';
-export 'src/usage_tracking.dart';
+export 'src/auto_snapshotting/auto_snapshotting.dart';
+export 'src/auto_snapshotting/model.dart';

pkgs/memory_usage/lib/src/auto_snapshotting/DEPENDENCIES.md

@@ -0,0 +1,21 @@
+<!---
+Generated by https://github.com/polina-c/layerlens
+Dependencies that create loops (inversions) are marked with `!`.
+-->
+
+```mermaid
+flowchart TD;
+_snapshot.dart-->_util.dart;
+_snapshot.dart-->model.dart;
+_usage_event.dart-->_util.dart;
+_usage_event.dart-->model.dart;
+auto_snapshotting.dart-->_snapshot.dart;
+auto_snapshotting.dart-->_usage_event.dart;
+auto_snapshotting.dart-->model.dart;
+```
+
+### Inversions
+In this folder: 0
+
+Including sub-folders: 0
+

pkgs/memory_usage/test/_snapshot_test.dart

@@ -4,7 +4,7 @@
 
 import 'dart:io';
 
-import 'package:memory_usage/src/_snapshot.dart';
+import 'package:memory_usage/src/auto_snapshotting/_snapshot.dart';
 import 'package:test/test.dart';
 
 void main() {