IoUringAssmEngine: Add start/stop() for frame assembly.

With these two functions implemented, this class now actually
assembles frames.

stimBuffApis/livoxGen1/ioUringAssemblyEngine.h

@@ -12,6 +12,7 @@
 #include <liburing.h>
 #include <boost/asio/io_service.hpp>
 #include <boost/asio/deadline_timer.hpp>
+#include <boost/asio/posix/stream_descriptor.hpp>
 #include <livoxProto1/device.h>
 #include "frameAssemblyDesc.h"
 
@@ -28,7 +29,8 @@ public:
 
 	bool setup();
 	void finalize();
-	void resetAndAssembleFrame();
+	void resetAndAssembleFrame(
+		std::function<void(void*)> onCqeReady);
 	void stop();
 
 	// Telemetry helpers
@@ -48,13 +50,19 @@ private:
 
 	// Eventfd for CQE notifications (used with boost's unified loop)
 	int eventfdFd;
+	std::unique_ptr<boost::asio::posix::stream_descriptor> eventfdDesc;
+	uint64_t eventfd_value;  // Buffer for async_read_some
 	// Point cloud data socket descriptor
 	std::shared_ptr<boost::asio::posix::stream_descriptor> pcloudDataFdDesc;
 
 	// Stall detection timer
 	boost::asio::deadline_timer stallTimer;
+	// Callback for CQE notifications (called with user_data from each CQE)
+	std::function<void(void*)> onCqeReadyCallback;
 
 	void cancelIncompleteAndFillDummies();
+	void onEventfdRead(
+		const boost::system::error_code& error, std::size_t bytes_transferred);
 };
 
 } // namespace stim_buff