Remove Event class

[wearhere]

We can just use the DOM Event class instead:

const e = new Event('event_name', { cancelable: true });
e.preventDefault();
console.log(e.defaultPrevented); // 'true'

Note that the third line there is technically a breaking change for SDK clients, from here—if they were reading that property vs. just calling preventDefault. But since they probably aren't and our usage is pretty low at the moment, if this is fixed in the near future, I'd just call the change a patch.

Another alternative to avoid making a breaking change is to do

Object.defineProperty(Event.prototype, 'isDefaultPrevented', {
  get() { return this.defaultPrevented; }
});