Function push

docs/external/js/react-dom.development.js:10784–10793

(cursor, value, fiber)

  }

  function push(cursor, value, fiber) {
    index++;
    valueStack[index] = cursor.current;

    {
      fiberStack[index] = fiber;
    }

    cursor.current = value;
  }

  var warnedAboutMissingGetChildContext;