A common platform interface for the flutter_js plugin.

This interface allows platform-specific implementations of the flutter_js plugin, as well as the plugin itself, to ensure they are supporting the same interface.


To implement a new platform-specific implementation of flutter_js, extend FlutterJsPlatform with an implementation that performs the platform-specific behavior, and when you register your plugin, set the default FlutterJsPlatform by calling FlutterJsPlatform.instance = MyFlutterJsPlatform().