adding an option for the concurrency limit

packages/labs/prefetch/README.md

@@ -92,6 +92,28 @@ export default {
 ```
 </details>
 
+<details>
+  <summary><strong>config.throttle</strong></summary>
+  
+  <br/>
+  
+By default the prefetch script will only prefetch one link at a time. This behavior can be changed in your `astro.config.*` file to increase the limit for concurrent downloads.
+  
+  <br/>
+
+```js
+import prefetch from '@astrojs/prefetch';
+
+export default {
+  // ...
+  integrations: [prefetch({
+    // Allow up to three links to be prefetched concurrently
+    throttle: 3
+  })],
+}
+```
+</details>
+
 ## Examples
 
 > Coming soon!

packages/labs/prefetch/src/client.ts

@@ -1,4 +1,4 @@
-import throttle from 'throttles';
+import throttles from 'throttles';
 import requestIdleCallback from './requestIdleCallback.js';
 
 const events = ['mouseenter', 'touchstart', 'focus'];
@@ -63,10 +63,16 @@ export interface PrefetchOptions {
 	 * @default "a[href][rel='prefetch']"
 	 */
 	selector?: string;
+	/**
+	 * The number of pages that can be prefetched concurrently.
+	 * 
+	 * @default 1
+	 */
+	throttle?: number;
 }
 
-export default function prefetch({ selector = 'a[href][rel="prefetch"]' }: PrefetchOptions) {
+export default function prefetch({ selector = 'a[href][rel="prefetch"]', throttle = 1 }: PrefetchOptions) {
-	const [toAdd, isDone] = throttle();
+	const [toAdd, isDone] = throttles(throttle);
 
 	observer =
 		observer ||