docs: update docs on deck.gl integration (#13)

docs/api-reference/components/map.md

@@ -40,9 +40,12 @@ export default App;
 
 ## DeckGL Integration
 
+### Using the `Map` as a child of `DeckGL`
+
 To use deck.gl with the `Map` component wrap the `Map` component with
-the [DeckGL React component](https://deck.gl/docs/get-started/using-with-react). The following props need to be defined
-and passed to the DeckGL component:
+the [DeckGL React component](https://deck.gl/docs/get-started/using-with-react).
+
+The following props need to be defined and passed to the DeckGL component:
 
 - `intialViewState`
 - `layers`
@@ -53,18 +56,53 @@ Make sure that the controller is always set to true and an initial view state is
 well with the Google Maps Platform map, set the `limitTiltRange` function, which can be imported from the Google Maps React
 library, to `onViewStateChange`.
 
-To add a layer to the map, add the layer to the layers array.
-
 ```tsx
-<APIProvider apiKey={'Your API key here'}>
-  <DeckGL
-    initialViewState={INITIAL_VIEW_STATE}
-    layers={layers}
-    controller={true}
-    onViewStateChange={limitTiltRange}>
-    <Map {...GOOGLE_MAPS_MAP_OPTIONS} />
-  </DeckGL>
-</APIProvider>
+import {limitTiltRange} from '@vis.gl/react-google-maps';
+
+const App = () => (
+  <APIProvider apiKey={'Your API key here'}>
+    <DeckGL
+      initialViewState={INITIAL_VIEW_STATE}
+      layers={layers}
+      controller={true}
+      onViewStateChange={limitTiltRange}>
+      <Map {...GOOGLE_MAPS_MAP_OPTIONS} />
+    </DeckGL>
+  </APIProvider>
+);
+```
+
+### Using GoogleMapsOverlay
+
+Alternatively, you can also use the `GoogleMapsOverlay` provided by the `@deck.gl/google-maps` package to render deck.gl
+content via Maps API `WebGlOverlayView`. An example for this can be found in [`./examples/deckgl-overlay`](https://github.com/visgl/react-google-maps/tree/1a0ac6e13d15ceda5212d310ffc2370ffdd90e65/examples/deckgl-overlay).
+
+For this you have to implement your own component and add it to the `Map` component.
+A simplified version of this would be:
+
+```javascript
+import {useEffect, useMemo} from 'react';
+import {useMap} from '@vis.gl/react-google-maps';
+import {GoogleMapsOverlay} from '@deck.gl/google-maps';
+
+export const DeckGlOverlay = ({layers}) => {
+  const deck = useMemo(() => new GoogleMapsOverlay({interleaved: true}), []);
+
+  const map = useMap();
+  useEffect(() => deck.setMap(map), [map]);
+  useEffect(() => deck.setProps({layers}), [layers]);
+
+  // no dom rendered by this component
+  return null;
+};
+
+const App = () => (
+  <APIProvider apiKey={API_KEY}>
+    <Map {...mapProps}>
+      <DeckGlOverlay layers={deckGlLayers} />
+    </Map>
+  </APIProvider>
+);
 ```
 
 ## Props