Issue title: [BUG]:when i called stopRecorder() and then checked the file, it does not exist!!
 Issue body: some one the same?
 Comments: 
 Comment 0: besides i can not set the audioSource field when startRecorder(), because the AudioSource type is not exported
<img width="578" alt="image" src="https://user-images.githubusercontent.com/12596042/170076459-87690ff8-2ef8-4e4e-a78a-656003fc165c.png">

 Comment 1: after i move the record logic from bloc to widget, the record file can be saved , but the player throw platform exception when playing the local file (the player can play remote file normally), 
 Comment 2: Same 

flutter_sound: ^9.2.13
Flutter: 2.10.4
 Comment 3: I found that although the file exists, but it is empty.
```
 var filePath = await _mRecorder.stopRecorder();
                File file = File(filePath!);
                if (file.existsSync()) {
                  print("file exist ${file.lengthSync()}");
                }
```
flutter: file exist 0

 Comment 4: > 1. Yes, the file path must be either a temporary file name (without any slash) or a complete file path pointing to a valid space in which we are allowed to write. You will probably use 'path_provider' plugin to build a correct file path. If you decide to specify a temporary file name, the full path will be returned during 'closeRecorder'.
> 2. Yes, 'audio session' is now very useful (since 9.0.x). Someone promised to write a guide about this, with examples, but he/she never completed this. A Pull Request by someone else is needed.

I did this fix and now the file exists but its empty too like @Allenxuxu comment

  flutter_sound: ^9.2.13 issue on iOS only
{'source': 'GithubIssues', 'repo_name_with_owner': 'Canardoux/flutter_sound', 'issue_id': 1246635695, 'repo_stars': 112.0}