UNSAFE_componentWillMount() {}
        UNSAFE_componentWillUpdate() {}
        UNSAFE_componentWillReceiveProps() {}
        render() {
          return (
            <StrictMode>
              <Wrapper />
            </StrictMode>
          );
        }
      }
      function Wrapper({children}) {
        return (
          <div>
            <Bar />
            <Foo />
          </div>
        );
      }
      class Foo extends React.Component {
        UNSAFE_componentWillReceiveProps() {}
        render() {
          return null;
        }
      }
      class Bar extends React.Component {