Enhance ad experiences with HLS interstitials

// Creating a single point interstitial event
 
let pointEvent = AVPlayerInterstitialEvent(primaryItem: playerItem, time: ten)

pointEvent.timelineOccupancy = .singlePoint

// Creating a fill interstitial event
    
let fillEvent = AVPlayerInterstitialEvent(primaryItem: playerItem, time: ten)

fillEvent.timelineOccupancy = .fill
fillEvent.plannedDuration = CMTime(value: 15, timescale: 1)

// Creating a fill interstitial event supplementing primary
 
let fillEvent2 = AVPlayerInterstitialEvent(primaryItem: playerItem, time: ten)

fillEvent2.supplementsPrimaryContent = true
fillEvent2.timelineOccupancy = .fill
fillEvent2.plannedDuration = CMTime(value: 15, timescale: 1)

// Create AVPlayerItem and obtain its integrated timeline

let item = AVPlayerItem(url: ...)
let integratedTimeline = item.integratedTimeline

//  Any time we need a new representation of the timeline state, we can request for a snapshot
let snapshot = integratedTimeline.currentSnapshot

//  Using our snapshot, we can build a simple transport bar
drawUISlider(start: .zero, duration: snapshot.duration, currentPosition: snapshot.currentTime)

// Draw single-point interstitials on the transport bar
let pointSegments = snapshot.segments.filter { segment in
    segment.segmentType == .interstitial &&
    segment.interstitialEvent?.timelineOccupancy == .singlePoint
}
for segment in pointSegments {
    drawPoint(position: segment.timeMapping.target.start)
}

// Draw range interstitials on the transport bar
let highlightFillSegments = snapshot.segments.filter { segment in
    if (segment.segmentType == .interstitial) {
        if let interstitialEvent = segment.interstitialEvent {
            return interstitialEvent.timelineOccupancy == .fill &&
                   !interstitialEvent.supplementsPrimaryContent
        }
    }
    return false
}

for segment in highlightFillSegments {
    let range = segment.timeMapping.target
    highlightRegion(start: range.start, end: range.end)
}

// Listen to integrated timeline notifications to update our logic

for await _ in NotificationCenter.default.notifications(named: AVPlayerItemIntegratedTimeline.snapshotsOutOfSyncNotification, object: integratedTimeline) {

    let reason = _.userInfo![AVPlayerItemIntegratedTimeline.snapshotsOutOfSyncReasonKey] 
                as! AVPlayerIntegratedTimelineSnapshotsOutOfSyncReason
                
    switch(reason) {
    case .segmentsChanged:
        redrawTransportBar(snapshot: integratedTimeline.currentSnapshot)
    case .currentSegmentChanged:
        updatePlayerControls(snapshot: integratedTimeline.currentSnapshot)
    }
}

// Set contentMayVary to false for SharePlay support
let event = AVPlayerInterstitialEvent(primaryItem: playerItem, time: ten)
event.contentMayVary = false
event.timelineOccupancy = .fill
event.plannedDuration = CMTime(value: 15, timescale: 1)
event.supplementsPrimaryContent = truensert code snippet.