void addStream(MediaStream stream, [Map mediaConstraints])

Source 

void addStream(MediaStream stream, [Map mediaConstraints]) {
  if (mediaConstraints != null) {
    _blink.BlinkRTCPeerConnection.instance.addStream_Callback_2_(unwrap_jso(this), unwrap_jso(stream), convertDartToNative_Dictionary(mediaConstraints));
    return;
  }
  _blink.BlinkRTCPeerConnection.instance.addStream_Callback_1_(unwrap_jso(this), unwrap_jso(stream));
  return;
}