add notes on ably drivers

Author: taylorotwell

broadcasting.md

@@ -115,6 +115,9 @@ The [laravel-websockets](https://github.com/beyondcode/laravel-websockets) and [
 <a name="ably"></a>
 ### Ably
 
+> **Note**
+> The documentation below discusses how to use Ably in "Pusher compatibility" mode. However, the Ably team maintains a broadcaster and Echo client that is able to take advantage of the unique capabilities offered by Ably. For more information on using the Ably maintained drivers, please [consult Ably's Laravel broadcaster documentation](https://github.com/ably/laravel-broadcaster).
+
 If you plan to broadcast your events using [Ably](https://ably.com), you should install the Ably PHP SDK using the Composer package manager:
 
 ```shell
@@ -208,6 +211,9 @@ window.Echo = new Echo({
 <a name="client-ably"></a>
 ### Ably
 
+> **Note**
+> The documentation below discusses how to use Ably in "Pusher compatibility" mode. However, the Ably team maintains a broadcaster and Echo client that is able to take advantage of the unique capabilities offered by Ably. For more information on using the Ably maintained drivers, please [consult Ably's Laravel broadcaster documentation](https://github.com/ably/laravel-broadcaster).
+
 [Laravel Echo](https://github.com/laravel/echo) is a JavaScript library that makes it painless to subscribe to channels and listen for events broadcast by your server-side broadcasting driver. You may install Echo via the NPM package manager. In this example, we will also install the `pusher-js` package.
 
 You may wonder why we would install the `pusher-js` JavaScript library even though we are using Ably to broadcast our events. Thankfully, Ably includes a Pusher compatibility mode which lets us use the Pusher protocol when listening for events in our client-side application: