close method
Permanently releases the controller and its platform resources.
Repeated calls return the same cleanup operation.
Implementation
Future<void> close() {
final Future<void>? existing = _closeFuture;
if (existing != null) {
return existing;
}
final WebViewController ownedController = controller;
_controller = null;
return _closeFuture = Future<void>.sync(
ownedController.platform.closeOffscreenWebView,
);
}