Component: Sentinel

[sam-goodwin]

Provide a new primitive Component, Sentinel, for watching the system, detecting anomalies and responding.

This is effectively a ReadModel+Policy.

Question: is it a new primitive or an composite of ReadModel and a Policy? Personally, I prefer it to be a new primitive since it will aid in visualization and customization.

[ryan-mars]

I believe we've hit upon a gap in Event Storming and perhaps this should be a primitive.

[ryan-mars]

Hopefully we get a response:

https://twitter.com/ryan_marsh/status/1412457682523590660?s=20