set(uniqueIdentifier) {
    if (this._ids[uniqueIdentifier]) {
      throw new Error(
        `Attempting to use the ID ${uniqueIdentifier}, but it's already been used`
      );
    }

    if (isNumber(uniqueIdentifier) && +uniqueIdentifier >= this._nextId) {
      this._nextId = +uniqueIdentifier + 1;
    }

    this._ids[uniqueIdentifier] = true;
  }
Registers `uniqueIdentifier` as used.

    This method should throw is `uniqueIdentifier` has already been taken.

    @method set
    @param {String|Number} uniqueIdentifier
    @public