[audio_streamer 4.0.0] Platform messages are sent from non-platform thread.

### Device / Emulator and OS
- Device: iOS Simulator or any other
- OS: iOS 17.0 or other

### Describe the bug
[VERBOSE-2:shell.cc(1004)] The 'audio_streamer.eventChannel' channel sent a message from native to Flutter on a non-platform thread. Platform channel messages must be sent on the platform thread. Failure to do so may result in data loss or crashes, and must be fixed in the plugin or application code creating that channel.
See https://docs.flutter.dev/platform-integration/platform-channels#channels-and-platform-threading for more information.

### To Reproduce
Run on any device.

### Expected behavior
Platform messages are sent from platform main thread.

### Flutter doctor
[✓] Flutter (Channel stable, 3.13.6, on macOS 14.0 23A344 darwin-x64, locale ru-RU)
[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.1)
[✓] Xcode - develop for iOS and macOS (Xcode 15.0)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2022.3)
[✓] VS Code (version 1.68.1)
[✓] Connected device (3 available)
[✓] Network resources