createGroupChat method
override
    Creates a group Chat with the provided members and the authenticated
MyUser, optionally named.
Implementation
@override
Future<RxChatImpl> createGroupChat(
  List<UserId> memberIds, {
  ChatName? name,
}) async {
  Log.debug('createGroupChat($memberIds, $name)', '$runtimeType');
  final ChatData chat = _chat(
    await _graphQlProvider.createGroupChat(memberIds, name: name),
  );
  return _putEntry(chat);
}