What is the best way to handle child timelines that have a infinite duration?
You can't just `TimelineMax.add` an infinite child timeline because they would block and cause the remaining events to never run in the root timeline.
The best way I have found is `restart`'ing the infinite child timeline in an `onStart` or `onComplete` event. One problem I have run into with this method is, if you seek past when the child timeline gets initiated, then it will never run.
When using `start`,