Create an event that fires, a condition that matches or some other solution to run an action only upon the first discovery irrespective of the host existence

Usecase - it would be useful to send an email when a new device is discovered, but currently that device temporarily going down will result in the next "up" cycle also counting as "discovered". This makes such notifications too noisy and not useful.

ZBXNEXT-306 is a little different, because it talks about ability to skip already existing hosts in network discovery actions.