我是一名学习iOS开发的学生，目前正在进行一个简单的人工智能项目，该项目利用SNAudioStreamAnalyzer对来自设备麦克风的音频流进行分类。我可以启动流并分析音频，没有问题，但我注意到，我似乎无法让我的应用停止分析并在完成后关闭音频输入流。在开始时，我初始化音频引擎并创建分类请求，如下所示：

private func startAudioEngine() {
        do {
            // start the stream of audio data
            try audioEngine.start()
            let snoreClassifier = try? SnoringClassifier2_0().model
            let classifySoundRequest = try audioAnalyzer.makeRequest(snoreClassifier)
            try streamAnalyzer.add(classifySoundRequest,
                                   withObserver: self.audioAnalyzer)
        } catch {
            print("Unable to start AVAudioEngine: \(error.localizedDescription)")
        }
    }

分类完音频流后，我尝试停止音频引擎并关闭音频流，如下所示：

private func terminateNight() {
        streamAnalyzer.removeAllRequests()
        audioEngine.stop()
        stopAndSaveNight()
        do {
            let session = AVAudioSession.sharedInstance()
            try session.setActive(false)
        } catch {
            print("unable to terminate audio session")
        }
        nightSummary = true
    }

但是，在调用terminateNight（）函数后，应用将继续使用麦克风并对传入的音频进行分类。以下是我的SNResultsObserving实现：

class AudioAnalyzer: NSObject, SNResultsObserving {
    var prediction: String?
    var confidence: Double?
    let snoringEventManager: SnoringEventManager
    
    internal init(prediction: String? = nil, confidence: Double? = nil, snoringEventManager: SnoringEventManager) {
        self.prediction = prediction
        self.confidence = confidence
        self.snoringEventManager = snoringEventManager
    }
    
    func makeRequest(_ customModel: MLModel? = nil) throws -> SNClassifySoundRequest {
        if let model = customModel {
            let customRequest = try SNClassifySoundRequest(mlModel: model)
            return customRequest
        } else {
            throw AudioAnalysisErrors.ModelInterpretationError
        }
    }
    
    func request(_ request: SNRequest, didProduce: SNResult) {
        guard let classificationResult = didProduce as? SNClassificationResult else { return }
        let topClassification = classificationResult.classifications.first
        let timeRange = classificationResult.timeRange
        self.prediction = topClassification?.identifier
        self.confidence = topClassification?.confidence
        if self.prediction! == "snoring" {
            self.snoringEventManager.snoringDetected()
        } else {
            self.snoringEventManager.nonSnoringDetected()
        }
    }
    
    func request(_ request: SNRequest, didFailWithError: Error) {
        print("ended with error \(didFailWithError)")
    }
    
    func requestDidComplete(_ request: SNRequest) {
        print("request finished")
    }
}

据我所知，在调用streamAnalyzer.removeAllRequests（）和audioEngine.stop（）时，应用会停止麦克风的流传输，并调用requestDidComplete函数，但这不是我得到的行为。