Persistence on iOS (and Android)

[Ben Rubinstein]

Is there such a thing as suspend/resume on iOS, or just startup and shutdown?

As far as I can see, when a LC app is suspended and resumed, it's in every way 
restarted.  Unless we save our state explicitly in a file/database/stack, and 
then reconstruct it on startup.  Is that correct, or am I missing something?

If that is correct - is the shutdown message a reliable signal that our app is 
going to be backgrounded, on which we can save whatever data we need to 
restore state?  Or do we have to save at every change in state, just in case 
we're about to be suspended?

... and is it the same approach on Android, or do we have suspend/resume there?

TIA,

Ben