Gateway issue/incompatibility: NORD is 0

[klauer]

Per @ZLLentz's summary of the long-standing issue:

camviewer uses the NORD field to get the number of active elements in the array to monitor, but the gateway sometimes bugs out and reports it as zero
area detector image streams initialize as 0 by 0 before receiving any frames, and this also does not play well with the loading of the blank image

[ZLLentz]

One more gateway incompatibility:
if a gateway is having a bad day, it will take longer than 1s to read the array data, leading to an error in camviewer instead of just a really laggy image

[klauer]

Long-term, I wonder if we should consider moving the data source from CA to Kafka or less preferably PVA? This sort of consistency issue is just non-existent there.

Come to think of it, this belongs in a new issue...