negotiated
By default, (false), data channels are negotiated in-band, where one side calls WebRtcPeerConnection.createDataChannel, and the other side listens to the event using the WebRtcPeerConnection.createDataChannel event handler. Alternatively (true), they can be negotiated out of-band, where both sides call WebRtcPeerConnection.createDataChannel with an agreed-upon ID. Default: false.