WebRTC STUN check and adding multiple STUN servers

var pc = new RTCPeerConnection({iceServers: [
    {urls: 'stun:stun1.l.google.com:19302'},
    {urls: 'stun:stun2.l.google.com:19302'}
]});
pc.createDataChannel("testchannel");
pc.onicecandidate = function(e) {
  if(e.candidate){
    console.log(e.candidate.candidate);
  }
};
pc.createOffer().then(offer => pc.setLocalDescription(offer));