catchupSubscription - LiveStarted question

Take this code:

var catchUpSubscriptionSettings = new CatchUpSubscriptionSettings(1, 500, true, true,“CatchupTest”);

eventStoreConnection.SubscribeToStreamFrom(“myStream”,
-1,
CatchUpSubscriptionSettings.Default
(e,r) => {
//Event Appeared
},
(eventStoreCatchUpSubscription) =>{
//LiveStarted
}