Ridgefield needs minute-level aggregates from sensor events. Events may arrive out of order, and analytics consumers should not block the producers. Which architecture best fits?

1. A synchronous call from every sensor to every analytics consumer.
2. A nightly manual spreadsheet export using file-arrival order as event time.
3. Pub/Sub ingestion and Dataflow processing with event-time windows and a lateness policy.
4. A load balancer used as the only event aggregation engine.