launch method
Navigates to the given URL.
Implementation
@override
Future<void> launch(String url) async {
_ensureOpen();
final uri = Uri.tryParse(url);
if (uri == null ||
!const {'http', 'https', 'file'}.contains(uri.scheme.toLowerCase())) {
throw ArgumentError.value(
url,
'url',
'Desktop WebViews only allow http, https, and file URLs.',
);
}
await channel.invokeMethod("launch", {"url": url, "viewId": viewId});
}