get() {
        if (!this._events.len()) {
            return null;
        }
        let { key: time, value: event } = this._events.pop();
        if (time > 0) { /* advance */
            this._time += time;
            this._events.shift(-time);
        }
        return event;
    }
Locates the nearest event, advances time if necessary. Returns that event and removes it from the queue.
@returns {? || null} The event previously added by addEvent, null if no event available