Fix type confusion

src/server.hpp

@@ -110,6 +110,10 @@ private:
   int epollfd_ = -1;
   int listen_sockfd_ = -1;
 
+  // Unique tags for special events to avoid type confusion in epoll data union
+  static inline const char listen_socket_tag = 0;
+  static inline const char shutdown_pipe_tag = 0;
+
   // Private helper methods
   void setup_shutdown_pipe();
   void setup_signal_handling();