Refresh control performs a user initiated content refresh, typically in a table view, or refresh control is a specialized type of an activity indicator. It's hidden by default and becomes visible when dragging down on the view to be reloaded. In mail, for example, you can drag the list of inbox messages down to check the new messages. User refresh control to update content. It's a known and consistent way to do it. He's so used to they just pull down the page a spinner appears.
Pulling has the well known rubber band effect release and the content gets refreshed. It can include the title, as you see in this example. You can also see here that it might have a different background from automatic content updates as well. Although people appreciate being able to trigger an immediate content refresh, they also expect automatic refreshes, check your periodically. Don't make users responsible for initiating every update. Keep data fresh by updating it regularly.
If a user is in the middle of scrolling your content, do not refresh automatically, because it will break the user slow. Good example is a nine gag app. It does not refresh the feed automatically when you're viewing it. Or when you left it somewhere in the middle of the content. It requires a user action to refresh the content in that case. supply a title only fit adds value and make sure it's short.
Guidelines also say that you should not state in your app how to use it refresh control. So that means that this pattern we have an example of here when the icon and pull to refresh text display Right away, or appears shortly when you start pulling is not following the guideline. I don't have a strong personal opinion here. But I think people are used enough to the pull to refresh thing. So you really don't have to give them these tips. Here's another example of how poorly refresh might word.
The small title near the spinner tells us when the update was made. But what's more interesting than not bars title changes here. This is from iOS official news app. But this part is not mentioned anywhere in the guidelines. conclusion, we can do this too.