Use case

It would be useful to have typesafe event channels in pigeon as these currently have to be created manually (and type safety has to be ensured manually).

Proposal

Automatically translate Stream getters to event channels:

@HostApi()
abstract class VideoPlayerApi {
  // The following getter represents the new feature:
  Stream<VideoEvent> get videoEvents;
  void dispose();
  void setLooping(LoopingMessage msg);
  void setVolume(VolumeMessage msg);
  void play();
  PositionMessage position();
  void seekTo(PositionMessage msg);
  void pause();
  void setMixWithOthers(MixWithOthersMessage msg);
}

The above example is based on #66710 where an instance of this API represents a single instance of a video player, and so the videoEvents stream would map to an event channel for a particular video player instance.