Let us start here, from square one. No, from Zero!

reader/structuredmessage.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include "message.h"
+
+class StructuredMessage : public Message {
+public:
+    StructuredMessage(uint8_t node, uint8_t param, uint8_t cmd,
+                      uint8_t packet_id, std::vector<uint8_t> request_data);
+};