Feature request: a callback detecting whether certain conditions have been satisfied for a given duration

[JinraeKim]

Hi,
simulation sometimes requires the detection of whether a certain event has occured for a given duration.

For example, I would like to terminate simulation if a condition whether a scalar state (namely, u) is negative has been satisfied for 5 seconds.

It would be useful if such functionality is provided as an exported callback.

[ChrisRackauckas]

Yes, this could be an interesting feature.