visitNamedArgumentAsync method
Implementation
@override
Future<dynamic> visitNamedArgumentAsync(NamedArgument node) async {
  return MapEntry(node.identifier.name, await node.value.acceptAsync(this));
}@override
Future<dynamic> visitNamedArgumentAsync(NamedArgument node) async {
  return MapEntry(node.identifier.name, await node.value.acceptAsync(this));
}