maybeReady = function () {
  if (isReady || !isLoadingCompleted || readyHoldsCount > 0)
    return;

  isReady = true;

  // Run startup callbacks
  while (callbackQueue.length)
    (callbackQueue.shift())();

}
Allow to run callbacks on Storybook startup, after stories are imported
Based on Meteor.startup client side implementation
@see https://github.com/meteor/meteor/blob/24865b28a0689de8b4949fb69ea1f95da647cd7a/packages/meteor/startup_client.js