You are developing a streaming Dataflow pipeline for UrbanSonic Analytics , which collects noise level readings from hundreds of sensors installed near construction zones throughout the city. Each sensor records noise every 10 seconds and sends data to the pipeline only when levels exceed 70 dBA . Your goal is to calculate the average noise level for each sensor once data has been continuously received for more than 30 minutes , but the window should close if no data is received from the sensor for 15 minutes . What should you do?