show err_msg in Visual Studio debugger

webserver.cc

@@ -182,7 +182,8 @@ void Webserver::do_session(tcp::socket *socket)
             break;
         if (ec) {
             delete socket;
-            throw std::ios_base::failure(ec.message());
+            std::string err_msg(ec.message());
+            throw std::ios_base::failure(err_msg.c_str());
         }
 
         const auto method = req.method();