constructor(events = [], failureCount = 0) {
    /**
     * The number of failures in this run
     * @type {number}
     */
    this.failureCount = failureCount;
    /**
     * All relevant events emitted from the {@link Runner}.
     * @type {SerializableEvent[]}
     */
    this.events = events;

    /**
     * Symbol-like value needed to distinguish when attempting to deserialize
     * this object (once it's been received over IPC).
     * @type {Readonly<"SerializableWorkerResult">}
     */
    Object.defineProperty(this, '__type', {
      value: SERIALIZABLE_RESULT_NAME,
      enumerable: true,
      writable: false
    });
  }
Creates instance props; of note, the `__type` prop.

Note that the failure count is _redundant_ and could be derived from the
list of events; but since we're already doing the work, might as well use
it.
@param {SerializableEvent[]} [events=[]] - Events to eventually serialize
@param {number} [failureCount=0] - Failure count