Use case

The documentation and example of pigeon describe the usage of @HostApi, which is used to call into native code from flutter.
But Pigeon also supports @FlutterApi, which enables the native code to call into Flutter code, typically used for Steam-like updates that are not initiated from the Flutter side, but from the OS/native side.
This feature is not mentioned only briefly in the README and there are no examples that showcase it.

Proposal

Pigeon should have better documentation for@FlutterApi in the README and either add an example project or at least link to a third-party package that uses it.

In a quick search I only found these third-party projects using it:

• https://github.com/fluttercandies/ff_native_screenshot/ simple package for listening to native screenshots, good candidate IMO
• https://github.com/zero-li/flutter_pigeon_plugin very minimal example project using @FlutterApi, would be a good candidate but the documentation is in Chinese
• https://gitlab.com/twilio-flutter/conversations complex-ish package using @FlutterApi