IOS microphone permission

[yimu wei]

I created a WebRTC audio receiver. only receive audio.I don't want the APP to ask for microphone access.can anyone tell me how to do it ?

my code is :

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let mandatoryConstraints = ["OfferToReceiveAudio": "true","OfferToReceiveVideo": "false"]

let sdpConstraints = RTCMediaConstraints(mandatoryConstraints: mandatoryConstraints, optionalConstraints: nil)

self.remoteParticipant?.peerConnection?.offer(for: sdpConstraints, completionHandler: { (sessionDescription, error) in

     // set local sdp .....

})

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and sdp info： audio type is recvonly.