docs: add code snippet and blurb about experimentalDisableStreaming option

src/content/docs/en/guides/integrations-guide/react.mdx

@@ -186,6 +186,26 @@ export default defineConfig({
 });
 ```
 
+### Disable streaming (experimental)
+
+Astro streams the output of React components by default. However, you can disable this behavior by enabling the `experimentalDisableStreaming` option. This is particularly helpful for supporting libraries that don’t work well with streaming, like some CSS-in-JS solutions.
+
+To disable streaming for all React components in your project, configure `@astrojs/react` with `experimentalDisableStreaming: true`
+
+```js title="astro.config.mjs" ins={8}
+import { defineConfig } from 'astro/config';
+import react from '@astrojs/react';
+
+export default defineConfig({
+  // ...
+  integrations: [
+    react({
+      experimentalDisableStreaming: true,
+    }),
+  ],
+});
+```
+
 [astro-integration]: /en/guides/integrations-guide/
 
 [astro-ui-frameworks]: /en/guides/framework-components/#using-framework-components