This example demonstrates how React manages asynchronous data loading for D3 visualizations. The app uses React’s `useState` and `useEffect` hooks to fetch a remote CSV file via D3’s `csv` method, displaying a loading message until the data arrives. Once loaded, a custom `message` function computes and renders the file size in kilobytes, row count, and column count using `d3.csvFormat` and the data’s `columns` property. The result is shown as plain text in a `<pre>` element, highlighting the integration of D3’s data parsing with React’s component lifecycle.