@IBAction func recordingButtonTapped(_ sender: AnyObject) {
        if audioEngine.isRunning {
            audioEngine.stop()
            recognitionRequest.endAudio()
            recognitionTask.cancel()
            recordingButton.setTitle("Start Recording", for: [])
        } else {
            recordingButton.setTitle("Stop Recording", for: [])
        do {

        let audioSession = AVAudioSession.sharedInstance()
        try audioSession.setCategory(AVAudioSessionCategoryRecord)
        try audioSession.setMode(AVAudioSessionModeMeasurement)
        try audioSession.setActive(true, with: .notifyOthersOnDeactivation)
            if let inputNode = audioEngine.inputNode {
                recognitionRequest.shouldReportPartialResults = true
                recognitionTask = speechRecognizer.recognitionTask(with: recognitionRequest, resultHandler: { (result, error) in
                    if let result = result {
                        self.textView.text = result.bestTranscription.formattedString
                        if result.isFinal {
                            self.audioEngine.stop()
                            inputNode.removeTap(onBus: 0)
                            self.recordingButton.setTitle("Start Recording", for: [])
                        }
                    }
                })

                let recordingFormat = inputNode.outputFormat(forBus: 0)
                inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat, block: { (buffer, when) in
                    self.recognitionRequest.append(buffer)
                })
                audioEngine.prepare()
                try audioEngine.start()
            }
        } catch {
            // Handle errors
        }
    }//end of else