在HealthKit中查询vo2Max？

Question

在WWDC 2017上，Apple宣布增加vo2Max作为新的数量样本。为了返回vo2Max样本，必须有哪些变量？根据Vo2Max下的健康应用程序“Apple Watch在您进行严格的户外散步时记录您预测的vo2Max，或在锻炼应用中运行至少20分钟并持续进行心率测量。”听起来好像它不适用于第三方应用程序，但是在2017年WWDC 2017上的this剪辑会让它听起来好像应该可用吗？

在.running户外锻炼期间，以下代码即使在20分钟后也会返回并清空阵列：

func startVO2MaxQuery(from startDate: Date, updateHandler: @escaping ([HKQuantitySample]) -> Void) {
        let typeIdentifier = HKQuantityTypeIdentifier.vo2Max
        startQuery(ofType: typeIdentifier, from: startDate) { _, samples, _, _, error in
            guard let quantitySamples = samples as? [HKQuantitySample] else {
                print("Heart rate query failed with error: \(String(describing: error))")
                return
            }
            print("VO2Max samples = \(quantitySamples)")
            updateHandler(quantitySamples)

        }
    }



 private func startQuery(ofType type: HKQuantityTypeIdentifier, from startDate: Date, handler: @escaping
        (HKAnchoredObjectQuery, [HKSample]?, [HKDeletedObject]?, HKQueryAnchor?, Error?) -> Void) {
        let datePredicate = HKQuery.predicateForSamples(withStart: startDate, end: nil, options: .strictStartDate)
        let devicePredicate = HKQuery.predicateForObjects(from: [HKDevice.local()])
        let queryPredicate = NSCompoundPredicate(andPredicateWithSubpredicates:[datePredicate, devicePredicate])

        let quantityType = HKObjectType.quantityType(forIdentifier: type)!

        let query = HKAnchoredObjectQuery(type: quantityType, predicate: queryPredicate, anchor: nil,
                                          limit: HKObjectQueryNoLimit, resultsHandler: handler)
        query.updateHandler = handler
        healthStore.execute(query)

        activeDataQueries.append(query)
    }

权限

 private func requestAccessToHealthKit() {
let healthStore = HKHealthStore()

let allTypes = Set([HKObjectType.workoutType(),
                    HKSeriesType.workoutRoute(),
                    HKObjectType.quantityType(forIdentifier: .activeEnergyBurned)!,
                    HKObjectType.quantityType(forIdentifier: .heartRate)!,
                    HKObjectType.quantityType(forIdentifier: .vo2Max)!,
                    HKObjectType.quantityType(forIdentifier: .stepCount)!,
                    HKObjectType.quantityType(forIdentifier: .distanceWalkingRunning)!])

healthStore.requestAuthorization(toShare: allTypes, read: allTypes) { (success, error) in
    if !success {
        print("failed HealthKit Authorization from iPhone \(String(describing: error?.localizedDescription))")
    }

    print("Successful HealthKit Authorization directly from the watch")
}

}

还有什么我需要做的吗？ Apple的文档非常稀少。