text: import ResizeObserverPolyfill from './src/ResizeObserver';
  
  let ResizeObserver = ResizeObserverPolyfill;
  
  // Export existing implementation if it's available.
  if (typeof window.ResizeObserver === 'function') {
      ResizeObserver = window.ResizeObserver;
  }
  
  export default ResizeObserver;
  