Updates the Chat setup page to include setup instructions for chat-swift

content/chat/setup.textile

@@ -5,6 +5,7 @@ product: chat
 languages:
   - javascript
   - react
+  - swift
 ---
 
 Use these instructions to install, authenticate and instantiate the Chat SDK.
@@ -43,28 +44,29 @@ h2(#install). Install
 
 The Chat SDK is built on top of the Ably Pub/Sub SDK and uses that to establish a connection with Ably.
 
-Both SDKs are available as NPM modules and via CDN.
-
-h3(#npm). NPM
-
-Install the Pub/Sub SDK and the Chat SDK:
-
-```[sh]
-npm install @ably/chat
-```
-
-Import the SDKs into your project:
-
-```[javascript]
-import * as Ably from 'ably';
-import { ChatClient } from '@ably/chat';
-```
+blang[javascript,react].
+  h3(#npm). NPM
+
+  Install the Pub/Sub SDK and the Chat SDK:
+
+  ```[sh]
+  npm install @ably/chat
+  ```
+
+  Import the SDKs into your project:
+
+  ```[javascript]
+  import * as Ably from 'ably';
+  import ChatClient from '@ably/chat';
+  ```
+
+  ```[react]
+  import * as Ably from 'ably';
+  import ChatClient from '@ably/chat';
+  import { ChatClientProvider } from '@ably/chat/react';
+  ```
 
-```[react]
-import * as Ably from 'ably';
-import { ChatClient } from '@ably/chat';
-import { ChatClientProvider } from '@ably/chat/react';
-```
+blang[swift].
 
 blang[javascript].
   h3(#cdn). CDN
@@ -81,7 +83,30 @@ blang[javascript].
   </script>
   ```
 
-blang[react].
+blang[react,swift].
+
+blang[swift].
+  h3(#spm). Swift Package Manager
+
+  The SDK is distributed as a Swift Package and can be installed using Xcode or by adding it as a dependency in your package’s @Package.swift@.
+
+  To install the @ably-chat-swift@ package in your Xcode Project:
+    * Paste @https://github.com/ably/ably-chat-swift@ in the Swift Packages search box (Xcode project → Swift Packages.. . → @+@ button).
+    * Select the Ably Chat SDK for your target.
+
+  To install the @ably-chat-swift@ package in another Swift Package, add the following to your @Package.swift@:
+
+  ```[swift]
+  .package(url: "https://github.com/ably/ably-chat-swift", from: "0.1.0"),
+  ```
+
+  Import the SDK:
+
+  ```[swift]
+  import AblyChat
+  ```
+
+blang[javascript,react].
 
 h2(#instantiate). Instantiate a client
 
@@ -90,7 +115,7 @@ Instantiate a realtime client using the Pub/Sub SDK and pass the generated clien
 blang[react].
   Pass the @ChatClient@ into the "@ChatClientProvider@":https://sdk.ably.com/builds/ably/ably-chat-js/main/typedoc/functions/chat_react.ChatClientProvider.html. The @ChatClient@ instance will be available to all child components in your React component tree.
 
-blang[javascript].
+blang[javascript,swift].
 
 
 ```[javascript]
@@ -111,13 +136,27 @@ const App = () => {
 };
 ```
 
+```[swift]
+let realtimeOptions = ARTClientOptions()
+realtimeOptions.key = "<API_KEY>"
+realtimeOptions.clientId = "<clientId>"
+let realtime = ARTRealtime(options: realtimeOptions)
+let chatClient = DefaultChatClient(realtime: realtime, clientOptions: nil)
+```
+
 A "@ClientOptions@":/api/realtime-sdk#client-options object may be passed to the Pub/Sub SDK instance to further customize the connection, however at a minimum you must set an API key and provide a @clientId@ to ensure that the client is "identified":/auth/identified-clients.
 
 Additional options can also be passed to the Chat client to customize the following properties:
 
-|_. Property |_. Description |
-| logHandler | The function to call for each line of "log output":#logging. The default is @console.log@. |
-| logLevel | The verbosity of the "log output":#logging. Options are; @trace@, @debug@, @info@, @warn@, @error@ or @silent@. The default is @error@. |
+blang[javascript,react].
+  |_. Property |_. Description |
+  | logHandler | The function to call for each line of "log output":#logging. The default is @console.log@. |
+  | logLevel | The verbosity of the "log output":#logging. Options are; @trace@, @debug@, @info@, @warn@, @error@ or @silent@. The default is @error@. |
+
+blang[swift].
+  |_. Property |_. Description |
+  | logHandler | This is your own custom log handler conforming to the @LogHandler@ protocol. A single @log@ function is called for each line of "log output":#logging. The default implementation uses Swift's @Logger@. |
+  | logLevel | The verbosity of the "log output":#logging. Options are; @.trace@, @.debug@, @.info@, @.warn@, @.error@ or @.silent@. The default is @.error@. |
 
 h2(#logging). Logging
 
@@ -145,7 +184,20 @@ const App = => {
 };
 ```
 
-The @logHandler@ property is your own function that will be called for each line of log output generated by the Chat SDK.
+```[swift]
+let realtimeOptions = ARTClientOptions()
+realtimeOptions.key = "<API_KEY>"
+realtimeOptions.clientId = "<clientId>"
+let realtime = ARTRealtime(options: realtimeOptions)
+let clientOptions = ClientOptions(logHandler: SomeLogHandler(), logLevel: .debug)
+return DefaultChatClient(realtime: realtime, clientOptions: clientOptions)
+```
+
+blang[javascript,react].
+  The @logHandler@ property is your own function that will be called for each line of log output generated by the Chat SDK.
+
+blang[swift].
+  The @logHandler@ property is your custom @LogHandler@ implementation that will be called for each line of log output generated by the Chat SDK.
 
 The @logLevel@ sets the verbosity of logs that will be output by the SDK. The following log levels are available to set: