viewFile function
View file at the given url using external app.
Returns true on success and false if there was no corresponding app to handle the url.
Note: currently this function is implemented only on android. Use the url_launcher package on
other platforms in the meantime.
Implementation
Future<bool> viewFile(Uri uri, {String? chooserTitle}) => _channel
    .invokeMethod<bool>('viewFile', uri.toString())
    .then((result) => result ?? false);