[CarPlay] Recommended way to fetch images asynchronously

I'm working on adding CarPlay support for our audio app.

When returning instances of MPContentItem in response to the contentItemAtIndexPath: method, sometimes I need to fetch the artwork asynchronously (eg: network fetch). What is the recommended way to do this with the CarPlay API?

What I've tried so for is to return a populated instance of MPContentItem right away and at the same time trigger a fetch for the artwork. On completion of the fetch, I update the artwork property of the same instance that I previously returned, wrapping it with beginUpdates and endUpdates calls. This doesn't seem to work consistently, sometimes the art updates, other times it doesn't update. Usually when I scroll the item out of bounds and back in, it uses the correct art.

I've tested this approach both in a Simulator and in a car with CarPlay.

What is the correct way to perform these updates?

Thanks!