index.js

import React, {Suspense} from 'react';

const cars = loadCarsFromServer(); // Start loading early

const App = () => (
  <Suspense fallback={<h1>Loading cars</h1>}>
    <CarDetails />
  </Suspense>
);

const CarDetails = () => {
  const car = cars.read(); // Syncronous, blocking call
  return (<h1>{car.name}</h1>);
}