The subscribe request is different than LibertasClusterReadReq in that an event id can be set as "urgent". The minInterval and maxInterval are in seconds.
The effective minInterval and maxInterval may be different due to multiple agents' different requirement and device's settings.
The maxInterval affects the report timeout. The timeout detection is done by the underlying Libertas OS. Thing-App task can just keep idling until some report or error happens.
Represents a cluster subscription request of a device.