docs: function generateBeaconStreamAndSecrets(publicKeysToNotify,
                                          ecdhForLocalDevice,
                                          secondsUntilExpiration) {
    var beaconStreamWithPreAmble =
      generatePreambleAndBeacons(publicKeysToNotify, ecdhForLocalDevice,
        secondsUntilExpiration);
  
    if (!beaconStreamWithPreAmble) {
      return null;
    }
  
    var pskMap = generatePskSecrets(publicKeysToNotify, ecdhForLocalDevice,
      beaconStreamWithPreAmble);
  
    return {
      beaconStreamWithPreAmble: beaconStreamWithPreAmble,
      keyAndSecret: pskMap
    };
  }