Fix some issues with transferring conn back to server

src/server.hpp

@@ -142,9 +142,9 @@ private:
    * This method is thread-safe and can be called from any thread.
    * The connection will be re-added to the epoll for continued processing.
    *
-   * @param connection Raw pointer to the connection being released back
+   * @param connection Unique pointer to the connection being released back
    */
-  void receiveConnectionBack(Connection *connection);
+  void receiveConnectionBack(std::unique_ptr<Connection> connection);
 
   // Make non-copyable and non-movable
   Server(const Server &) = delete;