Push Notification Doze Gate (2D): Priority, Collapse-Key & TTL

Every push notification your phone receives is quietly triaged by the OS before it ever reaches you. This simulator renders that pipeline as a 2D message flow between a server node and a device node: high-priority pushes (calls, chats) pass straight through no matter what, while normal-priority pushes (analytics pings, background refreshes) are held at a periodic Doze maintenance-window gate that only opens on a cycle. Messages that share a collapse-key get deduplicated the instant a newer one arrives, and any message still queued when its TTL runs out is dropped for good. Live counters track delivered, TTL-expired, and collapsed messages, plus the average end-to-end latency, and a scrolling strip chart shows queue depth over time — so you can see exactly how send rate, priority mix, gate timing, and TTL trade off against each other, the same mechanics that govern real FCM and APNs delivery.