diff --git a/redfish-core/include/subscription.hpp b/redfish-core/include/subscription.hpp
index 2a3d73d..7fe2fdc 100644
--- a/redfish-core/include/subscription.hpp
+++ b/redfish-core/include/subscription.hpp
@@ -58,7 +58,8 @@
     ~Subscription() = default;
 
     // callback for subscription sendData
-    void resHandler(const crow::Response& res);
+    void resHandler(const std::shared_ptr<Subscription>& /*self*/,
+                    const crow::Response& res);
 
     void sendHeartbeatEvent();
     void scheduleNextHeartbeatEvent();
@@ -91,8 +92,8 @@
     std::shared_ptr<crow::ConnectionPolicy> policy;
     crow::sse_socket::Connection* sseConn = nullptr;
 
-    std::optional<crow::HttpClient> client;
     boost::asio::steady_timer hbTimer;
+    std::optional<crow::HttpClient> client;
 
   public:
     std::optional<filter_ast::LogicalAnd> filter;