what is the purpose of "update-cycle" for an event in the configuration json file

[mogar]

Several example configuration json files show events offered with an "update-cycle". I don't see this documented in the user's guide anywhere.

Does this set how often the event is expected to occur? In other words, are we expected to call app_->notify for that event at the given rate?

What sets how often offer messages for the event are sent? Do we need to send each offer message manually?