从iOS上的麦克风输入进行语音活动检测

I'm developing an iOS app that does voice based AI; i.e. it's meant to take voice input from the microphone, turn it into text, send it to an AI agent, then output the returned text through the speaker. I've got everything working, though using a button to start and stop recording the speech (SpeechKit for voice recognition, API.AI for the AI, Amazon's Polly for the output).I'm developing an iOS app that does voice based