IoUringAssmEngn: Add ~16ms bridged delay in finalize()

See the diff of the todo file within this patch for more
details.

This is to eliminate the possibility of having an in-flight async
contin access metadata that we destroyed in finalize().

stimBuffApis/livoxGen1/ioUringAssemblyEngine.cpp

@@ -178,6 +178,36 @@ void IoUringAssemblyEngine::finalize()
 {
 	bool wasAcceptingRequests = stop();
 
+	{
+		auto& ioService = smoHooksPtr->ComponentThread_getSelf()->getIoService();
+		AsynchronousBridge bridge(ioService);
+		boost::asio::deadline_timer timeoutTimer(ioService);
+
+		/**	EXPLANATION:
+		 * We wait for IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS + 1 ms to ensure
+		 * that any in-flight assembly operation has definitely finished. We add
+		 * 1 ms because an operation could have just begun when we call stop(),
+		 * and then it would timeout in IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS
+		 * ms and potentially touch state that we have begun to destroy since it
+		 * only just exited the delay. The extra 1 ms ensures that even if an
+		 * operation started at the last possible moment, it will have completed
+		 * or timed out before we proceed with cleanup.
+		 */
+		timeoutTimer.expires_from_now(
+			boost::posix_time::milliseconds(
+				IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS + 1));
+		timeoutTimer.async_wait(
+			[&bridge](const boost::system::error_code& error)
+			{
+				(void)error;
+
+				// Always signal complete, whether timeout expired or was cancelled
+				bridge.setAsyncOperationComplete();
+			});
+
+		bridge.waitForAsyncOperationCompleteOrIoServiceStopped();
+	}
+
 	if (eventfdFd >= 0)
 	{
 		io_uring_unregister_eventfd(&ring);
@@ -446,10 +476,10 @@ public:
 				context.get(), context,
 				std::placeholders::_1, std::placeholders::_2));
 
-		// Set up timeout timer for CONFIG_STIMBUFF_FRAME_PERIOD_MS/2 ms
+		// Set up timeout timer for IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS ms
 		engine.stallTimer.expires_from_now(
 			boost::posix_time::milliseconds(
-				CONFIG_STIMBUFF_FRAME_PERIOD_MS / 2));
+				IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS));
 		engine.stallTimer.async_wait(
 			std::bind(&AssembleFrameReq::assembleFrameReq2_1,
 				context.get(), context,