1. When does the code in a loader function run?



2. What are some benefits of using a data loader function
   instead of fetching our data in a useEffect in a component?
   
   
   
3. What change do we need to make to our BrowserRouter before
   we can use loaders (or any of the new data-layer API features)
   in our app?
   
   
   
4. What are the steps we need to take in order to use
   a loader on any given route?