AVSpeechSynthesizer spoken text is being listened by the AVAudioSession record. How to ignore audio output from AVSpeechSynthesizer when recording

问题

My startRecording function sets up an AVAudioSession for record, which is called on pressing a mic button.

Before pressing the mic I am using an AVSpeechSynthesizer to speak some text. If I press the record button before the AVSpeechSynthesizer speech ends that speech is being recorded by AVAudioSession.

How do I ignore the speech spoken by my AVSpeechSynthesizer and just record speech speaken by the user through a microphone?

来源：https://stackoverflow.com/questions/61260287/avspeechsynthesizer-spoken-text-is-being-listened-by-the-avaudiosession-record