dispatchEvent = (type) => {
      triggerEvent.call(this.player, this.player.media, `ads${type.replace(/_/g, '').toLowerCase()}`);
    }
This is where all the event handling takes place. Retrieve the ad from the event. Some
events (e.g. ALL_ADS_COMPLETED) don't have the ad object associated
https://developers.google.com/interactive-media-ads/docs/sdks/html5/v3/apis#ima.AdEvent.Type
@param {Event} event