Occurs in Fiber with multiple instances of the React package (which can't share current owner).
getCurrentFiberStackAddendum(),
    );
  };
}
const {
  createWorkInProgress,
  createFiberFromElement,
  createFiberFromFragment,
  createFiberFromText,
  createFiberFromCoroutine,
  createFiberFromYield,
  createFiberFromPortal,
} = ReactFiber;
const isArray = Array.isArray;
const {
  FunctionalComponent,
  ClassComponent,
  HostText,
  HostPortal,
  CoroutineComponent,
  YieldComponent,
  Fragment,
} = ReactTypeOfWork;
const {NoEffect, Placement, Deletion} = ReactTypeOfSideEffect;
const ITERATOR_SYMBOL = typeof Symbol === 'function' && Symbol.iterator;
const FAUX_ITERATOR_SYMBOL = '@@iterator'; 
const REACT_ELEMENT_TYPE =
  (typeof Symbol === 'function' && Symbol.for && Symbol.for('react.element')) ||
  0xeac7;
function getIteratorFn(maybeIterable: ?any): ?() => ?Iterator<*> {