NRF clients should honor the heartbeat returned by NF
Issue
From 3GPP 29.510 Chapter 5.2.2.3.2, release 17
The time interval at which the NRF shall be contacted is deployment-specific, and it is returned by the NRF to the NF Service Consumer as a result of a successful registration. When the NRF detects that a given NF has not updated its profile for a configurable amount of time (longer than the heart-beat interval), the NRF changes the status of the NF to SUSPENDED and considers that the NF and its services can no longer be discovered by other NFs via the NFDiscovery service. The NRF notifies NFs subscribed to receiving notifications of changes of the NF Profile that the NF status has been changed to SUSPENDED.
Solution
When we refactor the NRF client for all NFs, we should implement this behavior accordingly.