I am implementing push notifications for a web application running as a PWA on iPad using Web Push. When sending a push notification to the web application, I received a 410 response from the server. I would like to understand the cause and reason for receiving this 410 response. The library used for sending push notifications is a commonly used JavaScript Web Push library. Could you please explain under what circumstances Apple Web Push endpoints return a 410 response, and whether this indicates that the existing push subscription is no longer valid and should be re‑registered.