I am sending push notifications to the app with critical alerts, but there is a significant delay. If the number of target devices is 1000 or less, notifications will be received normally within a few seconds to a minute. Once the number of target devices exceeds 1000, some devices will arrive quickly (normally within a few seconds to 1 minute) and others will arrive late (3 minutes to 15 minutes, divided into hundreds of items). In severe cases, notifications to more than 80% of devices will be delayed. Example: If you send 3000 notifications at once, 　1 minute: Notify 400 items 　5 minutes: Notify 1000 items 　10 minutes: Notify 1000 items 　13 minutes: Notify 600 items *The timing of 5 minutes, 10 minutes, and 13 minutes changes every time and is not at regular intervals. We understand that according to the push notification specifications, sending several thousand messages at once is not a problem. Please let me know if there is a rule, such as sending 1000 items at a time, in order to deliver quickly and with minimal delay.