Boost asio and Russian text?

Question

C++ / C#

There is such a function

const string host = "api.adialca.com";
  string target = "/info.php?source=app&" + request;
  if (isMessage)
    target = "/info.php?source=app_message&" + request;
  string tmp = host + target;
  io_service service;
  ip::tcp::resolver resolver(service);
  ip::tcp::socket socket(service);
  connect(socket, resolver.resolve(host, "80"));
  http::request<http::string_body> req(http::verb::get, target, 11);
  req.set(http::field::host, host);
  req.set(http::field::user_agent, BOOST_BEAST_VERSION_STRING);
  http::write(socket, req);
  {
    boost::beast::flat_buffer buffer;
    http::response<http::dynamic_body> res;
    http::read(socket, buffer, res);
  }
  socket.shutdown(ip::tcp::socket::shutdown_both);

It works great with string, but how to rewrite it to wstring or wchar_t in order to use Russian in queries?