[Bug] Platform messages do not happen on the main thread on iOS

[navaronbracke]

Platform messages do not happen on the main thread on iOS. (have not tested MacOS)

Describe the bug
While fixing #1382 and running the example app to test my change, I had a warning in the console.
See the logs below.

Presumably we are missing switches to the main dispatch queue when sending events back?

Platform

• Android
• iOS
• Web
• Desktop

Platform OS version
Any version

How are you picking?
Using the example app

Details to reproduce the issue

• Run the example app on Flutter stable (3.13.6)
• Pick an image
• See the log

Error Log

[VERBOSE-2:FlutterDarwinContextMetalImpeller.mm(37)] Using the Impeller rendering backend.
flutter: The Dart VM service is listening on http://127.0.0.1:56395/L7zjkDB9z_k=/


***** Picker:<PHPickerViewController: 0x11301e3c0> didFinishPicking:(
    "<PHPickerResult: 0x600000291bc0>"
)
* -[FilePickerPlugin picker:didFinishPicking:] [Line 441]
flutter: FilePickerStatus.picking
[VERBOSE-2:shell.cc(1004)] The 'miguelruivo.flutter.plugins.filepickerevent' 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.
flutter: FilePickerStatus.done

Screenshots and/or video
N/A

Flutter Version details

[✓] Flutter (Channel stable, 3.13.5, on macOS 13.5.2 22G91 darwin-x64, locale
    en-BE)
    • Flutter version 3.13.5 on channel stable at
      /Users/navaronbracke/Documents/flutter
    • Upstream repository git@github.com:navaronbracke/flutter.git
    • FLUTTER_GIT_URL = git@github.com:navaronbracke/flutter.git
    • Framework revision 12fccda598 (3 weeks ago), 2023-09-19 13:56:11 -0700
    • Engine revision bd986c5ed2
    • Dart version 3.1.2
    • DevTools version 2.25.0

[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
    • Android SDK at /Users/navaronbracke/Library/Android/sdk
    • Platform android-34, build-tools 34.0.0
    • ANDROID_HOME = /Users/navaronbracke/Library/Android/sdk
    • Java binary at: /Applications/Android
      Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build
      17.0.6+0-17.0.6b802.4-9586694)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 15.0)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 15A240d
    • CocoaPods version 1.13.0

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2022.2)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build
      17.0.6+0-17.0.6b802.4-9586694)

[✓] VS Code (version 1.83.0)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.74.0

[✓] Connected device (3 available)
    • iPhone 15 Pro (mobile) • C2B006FF-ECB8-4D7A-B48F-1D3B1D3FE6D6 • ios            • com.apple.CoreSimulator.SimRuntime.iOS-17-0 (simulator)
    • macOS (desktop)        • macos                                • darwin-x64     • macOS 13.5.2 22G91 darwin-x64
    • Chrome (web)           • chrome                               • web-javascript • Google Chrome 117.0.5938.149

[✓] Network resources
    • All expected network resources are available.

• No issues found!

Additional context
N/A

[github-actions]

This issue is stale because it has been open for 14 days with no activity.

[navaronbracke]

I will work on this when I migrate the plugin to the plugin_platform_interface

[github-actions]

This issue is stale because it has been open for 14 days with no activity.

[github-actions]

This issue is stale because it has been open for 14 days with no activity.