src/vs/workbench/contrib/notebook/browser/notebookRendererMessagingServiceImpl.ts/NotebookRendererMessagingService/getScoped
class NotebookRendererMessagingService:	public getScoped(editorId: string): IScopedRendererMessaging {
		return {
			onDidReceiveMessage: Event.filter(this.onDidReceiveMessage, e => e.editorId === editorId),
			postMessage: (rendererId, message) => this.postMessage(editorId, rendererId, message),
		};
	}