src/vs/workbench/services/lifecycle/browser/lifecycleService.ts/BrowserLifecycleService/registerListeners
class BrowserLifecycleService:	private registerListeners(): void {

		// beforeUnload
		this.beforeUnloadDisposable = addDisposableListener(window, 'beforeunload', (e: BeforeUnloadEvent) => this.onBeforeUnload(e));
	}