Same as https://github.com/facebook/react/issues/10103, but for the server renderer. You can look at implementation in https://github.com/facebook/react/pull/11168 and do something very similar in `ReactPartialRenderer.js`.
}
      
      const nextElement = ((nextChild: any): ReactElement);
      const elementType = nextElement.type;
      switch (elementType) {
        case REACT_FRAGMENT_TYPE:
          const nextChildren = toArray(
            ((nextChild: any): ReactElement).props.children,
          );
          const frame: Frame = {
            domNamespace: parentNamespace,
            children: nextChildren,
            childIndex: 0,
            context: context,
            footer: '',
          };
          if (__DEV__) {
            ((frame: any): FrameDev).debugElementStack = [];
          }
          this.stack.push(frame);
          return '';
        case REACT_CALL_TYPE:
        case REACT_RETURN_TYPE:
          invariant(
            false,
            'The experimental Call and Return types are not currently ' +
              'supported by the server renderer.',
          );
        // eslint-disable-next-line-no-fallthrough
        default: