SpeechKit缺少语音结束功能？

Question

我使用新的SpeechKit框架实现了语音识别。
但是，我找不到任何关于如何实现自动语音结束检测的指示。

有人知道这是否是在某种程度上是可行的吗？

func startRecording() {

        // check if recognition task is running
        if recognitionTask != nil {
            recognitionTask?.cancel()
            recognitionTask = nil
        }

        // create an audio session for the audio recording
        let audioSession = AVAudioSession.sharedInstance()
        do {
            try audioSession.setCategory(AVAudioSessionCategoryRecord) // recording
            try audioSession.setMode(AVAudioSessionModeMeasurement) // measurement
            try audioSession.setActive(true, with: .notifyOthersOnDeactivation)
        } catch {
            print("audioSession properties weren't set because of an error")
        }

        // this will be sent to the Apple's servers
        recognitionRequest = SFSpeechAudioBufferRecognitionRequest()

        // check if the device has an audio input for recording
        guard let inputNode = audioEngine.inputNode else {
            fatalError("Audio engine has no input node")
        }

        guard let recognitionRequest = recognitionRequest else {
            fatalError("Unable to create an SFSpeechAudioBufferRecognitionRequest object")
        }

        // also partial results will be reported
        recognitionRequest.shouldReportPartialResults = true


        // start recognition, and finally return a final transcript
        recognitionTask = speechRecognizer?.recognitionTask(with: recognitionRequest, resultHandler: { result, error in

            var isFinal = false

            if result != nil {
                self.textView.text = result?.bestTranscription.formattedString
                isFinal = (result?.isFinal)!
            }

            // if there is no error, or result is final, stop everything
            if error != nil || isFinal {
                self.audioEngine.stop()
                inputNode.removeTap(onBus: 0)

                self.recognitionRequest = nil
                self.recognitionTask = nil

                self.microphoneButton.isEnabled = true
            }
        })

        let recordingFormat = inputNode.outputFormat(forBus: 0)

        // add an audio input to the request
        inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { buffer, when in
            self.recognitionRequest?.append(buffer)
        }

        // prepare and start the audio engine
        audioEngine.prepare()

        do {
            try audioEngine.start()
        } catch {
            print("audioEngine couldn't start because of an error.")
        }

        textView.text = "Say something, I'm listening!"
    }


}