Function unstable_wrapCallback

docs/external/js/react.development.js:2718–2731

(callback)

  }

  function unstable_wrapCallback(callback) {
    var parentPriorityLevel = currentPriorityLevel;
    return function () {
      // This is a fork of runWithPriority, inlined for performance.
      var previousPriorityLevel = currentPriorityLevel;
      currentPriorityLevel = parentPriorityLevel;

      try {
        return callback.apply(this, arguments);
      } finally {
        currentPriorityLevel = previousPriorityLevel;
      }
    };
  }

  function timeoutForPriorityLevel(priorityLevel) {
    switch (priorityLevel) {