指南

func prepare(_ format: AdFormat) async -> VideoAd? {
    do {
        let ad = try await ads.format(format)
        try await ad.load()
        ad.delegate = self
        return ad
    } catch {
        return nil                     // 这次该格式无填充
    }
}

async let overlay = prepare(.overlay)
async let pause = prepare(.pause)
async let linear = prepare(.linear)
(overlayAd, pauseAd, linearAd) = await (overlay, pause, linear)

let ad = try await ads.format(.pause)
if ad.price.value >= otherNetworkCPM {
    try await ad.load()
    pauseAd = ad
} else {
    try ad.reject(.outbid(winningPrice: otherNetworkCPM, winner: "Other network"))
}

do {
    pauseAd = try await ads.format(.pause)
} catch VideoAdError.noFill(let reason) {
    switch reason {
    case .noAdMatch: break             // 此刻没有广告活动适合这一集或这位观众
    case .geoRestricted: break         // 观众所在的国家不投放广告
    default: break                     // frequencyCap、contentUnsafe、temporaryError……
    }
}

ads.trackPlayhead(of: player)

ads.playheadProvider = { [weak self] in self?.player.currentTime ?? 0 }

let next = VideoAds(content: nextEpisode)
Task { nextLinear = try? await next.format(.linear); try? await nextLinear?.load() }

// 观众继续看下一集时：
ads.destroy()
ads = next
ads.trackPlayhead(of: player)     // 播放器现在播放下一集

KontextVideo.shared.user = .init(id: "user-1234", keywords: ["romance", "drama"])
KontextVideo.shared.regulatory = .init(coppa: false)
KontextVideo.shared.variantId = "B"     // 与 Kontext 约定的 A/B 测试