Feature Request: Stopping a signal

[SimonDanisch]

Is it simple to implement an optional stop signal for every lift?
Background: if I animate a large array, e.g. particles, it would be great if I can stop it at some point and clean up the resources.
Similar thing for cameras. It is sometimes simpler to just stop one camera and create a new one, instead of trying to recycle a pool of cameras.

Best,
Simon