livoxProto1: export getReturnModeReq; cache result in Device

commonLibs/livoxProto1/livoxProto1.cpp

@@ -90,4 +90,18 @@ void livoxProto1_device_disablePcloudDataReq(
 	device->disablePcloudDataReq(callback);
 }
 
+void livoxProto1_device_getReturnModeReq(
+	std::shared_ptr<livoxProto1::Device> device,
+	smo::Callback<livoxProto1_device_getReturnModeReqCbFn> callback
+)
+{
+	if (!device)
+	{
+		throw std::runtime_error(std::string(__func__)
+			+ ": Device pointer is null");
+	}
+
+	device->getReturnModeReq(callback);
+}
+
 } // extern "C"