History container

This history stores notification that have been sent.

This does not know much about the objects stored.

But it does know:
- old records are of no interest
- after records are searched, throw everything away
- in the scan, the match, and all of the ones closer to the head of the stack are of interest
- scan for records from the head (like a stack not a queue)

As we work through this, knowledge of the response code and notification may make things better