Description
Service regularly checks if there is a new version of the subscribers-offline-package available and if so, downloads it and updates local subscribers-offline-package cache model with relevant subscribers.
Service is supposed to be a singleton. It’s methods are not thread-safe.
Data
As global subscribers-offline-package contains all subscribers considered offline, each consumer, installed in a particular zone, will only care about subscribers with firebases from the groups it’s responsible for. This way, we can avoid unnecessary data processing and keep the system efficient.