/* ----- CONSTRUCTOR -----
function Worker(opt) {
    // Create the root parent for the proto chain, and the starting Worker.
    var root = Object.assign(Worker.convert(Promise.resolve()),
      JSON.parse(JSON.stringify(Worker.template)));
    var self = Worker.convert(Promise.resolve(), root);

    // Set progress, optional settings, and return.
    self = self.setProgress(1, Worker, 1, [Worker]);
    self = self.set(opt);
    return self;
  }