How to polling resources "on-demand" for Argonaut project

I figure out on “Argonaut Data Query Impl.” page that ‘lastUpdated’ in the meta resource is not a mandatory property. And also ‘history’ operation. But Apple’s Healthkit seems to do it with a lot of hospitals. Is there any trick? Or do I miss something?

That is an Implementation detail that is not part of the guide and is one of the reasons for current Argonaut subscription work.