Any warnings driven off of `warnAboutDeprecatedLifecycles` should use `shared/lowPriorityWarning` rather than `fbjs/lib/warning` to avoid thrashing automated tests.
if (typeof elementType === 'string') {
        return this.renderDOM(nextElement, context, parentNamespace);
      }
      switch (elementType) {
        case REACT_FRAGMENT_TYPE: {
          const nextChildren = toArray(
            ((nextChild: any): ReactElement).props.children,
          );
          const frame: Frame = {
            type: null,
            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.',
          );