Function startTransition

docs/external/js/react-dom.development.js:15657–15673

(setPending, config, callback)

  }

  function startTransition(setPending, config, callback) {
    var priorityLevel = getCurrentPriorityLevel();
    runWithPriority$1(priorityLevel < UserBlockingPriority$1 ? UserBlockingPriority$1 : priorityLevel, function () {
      setPending(true);
    });
    runWithPriority$1(priorityLevel > NormalPriority ? NormalPriority : priorityLevel, function () {
      var previousConfig = ReactCurrentBatchConfig$1.suspense;
      ReactCurrentBatchConfig$1.suspense = config === undefined ? null : config;

      try {
        setPending(false);
        callback();
      } finally {
        ReactCurrentBatchConfig$1.suspense = previousConfig;
      }
    });
  }

  function mountTransition(config) {
    var _mountState2 = mountState(false),