docs/bundle.js
function unbatchedUpdates(fn) {
    if (isBatchingUpdates && !isUnbatchingUpdates) {
      isUnbatchingUpdates = true;
      try {
        return fn();
      } finally {
        isUnbatchingUpdates = false;
      }
    }
    return fn();
  }
function unbatchedUpdates(fn) {
    if (isBatchingUpdates && !isUnbatchingUpdates) {
      isUnbatchingUpdates = true;
      try {
        return fn();
      } finally {
        isUnbatchingUpdates = false;
      }
    }
    return fn();
  }
TODO: Batching should be implemented at the renderer level, not inside the reconciler.