### Connect using WebSocket Secure (wss)

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Example of setting up a secure WebSocket connection (wss) for MQTT. Includes custom SSL validation logic.

```swift
import CocoaMQTT
import CocoaMQTTWebSocket
import Starscream

class WebSocketManager {
    
    private var mqttClient: CocoaMQTT?
    var message: String = ""
    var token: String = ""

    func setupMQTTClient(with token: String) {
        let socket = CocoaMQTTWebSocket(uri: "/mqtt")
        socket.enableSSL = true
        mqttClient = CocoaMQTT(clientID: token, host: "host", port: 443, socket: socket)
        mqttClient?.delegate = self
    }

    func connect() {
        guard let mqttClient = mqttClient else { return }
        mqttClient.connect()
    }
    
}

extension WebSocketManager: CocoaMQTTDelegate {
    
    func mqtt(_ mqtt: CocoaMQTT, didReceive trust: SecTrust, completionHandler: @escaping (Bool) -> Void) {
        // Implement your custom SSL validation logic here.
        // For example, you might want to always trust the certificate for testing purposes:
        completionHandler(true)
    }
    
    func mqtt(_ mqtt: CocoaMQTT, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust {
            if let serverTrust = challenge.protectionSpace.serverTrust {
                completionHandler(.useCredential, URLCredential(trust: serverTrust))
                return
            }
        }
        completionHandler(.performDefaultHandling, nil)
    }
    
    func mqttUrlSession(_ mqtt: CocoaMQTT, didReceiveTrust trust: SecTrust, didReceiveChallenge challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        
        print("\(#function), \n result:- \(challenge.debugDescription)")
    }
    
    func mqtt(_ mqtt: CocoaMQTT, didPublishAck id: UInt16) {
        print("Published message with ID: \(id)")
    }
    
    func mqtt(_ mqtt: CocoaMQTT, didUnsubscribeTopics topics: [String]) {
        print("Unsubscribed from topics: \(topics)")
    }
    
    func mqttDidPing(_ mqtt: CocoaMQTT) {
        print("MQTT did ping")
    }
    
    func mqttDidReceivePong(_ mqtt: CocoaMQTT) {
        print("MQTT did receive pong")
    }
    
    func mqttDidDisconnect(_ mqtt: CocoaMQTT, withError err: (any Error)?) {
        print("Disconnected from MQTT broker with error: \(String(describing: err))")
    }
    
    func mqtt(_ mqtt: CocoaMQTT, didConnectAck ack: CocoaMQTTConnAck) {
        print("Connected to MQTT broker with acknowledgment: \(ack)")
    }
    
    func mqtt(_ mqtt: CocoaMQTT, didReceiveMessage message: CocoaMQTTMessage, id: UInt16) {
        if let messageString = message.string {
            DispatchQueue.main.async {
                self.message = messageString
            }
            print("Received message: \(messageString) on topic: \(message.topic)")
        }
    }
    
}
```

--------------------------------

### Create MQTT 3.1.1 Instance over WebSocket

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Instantiate CocoaMQTT with WebSocket support for MQTT 3.1.1. This is a standard connection setup.

```swift
///MQTT 3.1.1
let websocket = CocoaMQTTWebSocket(uri: "/mqtt")
let mqtt = CocoaMQTT(clientID: clientID, host: host, port: 8083, socket: websocket)

// ...

_ = mqtt.connect()
```

--------------------------------

### CocoaPods Podfile for WebSockets

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Modify your Podfile to include the CocoaMQTT/WebSockets pod for WebSocket support. Execute 'pod install' after updating.

```ruby
use_frameworks!

target 'Example' do
    pod 'CocoaMQTT/WebSockets'
end
```

--------------------------------

### Import CocoaMQTT with Swift Package Manager

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Import the CocoaMQTT library after installing it via Swift Package Manager.

```swift
import CocoaMQTT
```

--------------------------------

### Get SSL Trust (Non-Linux/watchOS)

Source: https://github.com/emqx/cocoamqtt/wiki/FoundationStream

Retrieves the SSL trust and domain information. This method is only available on non-Linux and non-watchOS platforms.

```swift
public func sslTrust() -> (trust: SecTrust?, domain: String?)

```

--------------------------------

### Get SSL Trust Information

Source: https://github.com/emqx/cocoamqtt/wiki/WSStream

Retrieves SSL trust and domain information. This method is not available on Linux or watchOS.

```swift
func sslTrust() -> (trust: SecTrust?, domain: String?)
```

--------------------------------

### init()

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTLogger

Initializes a new instance of CocoaMQTTLogger.

```APIDOC
## Initializer: init()

### Description
Initializes a new instance of the CocoaMQTTLogger class.

### Signature
```swift
public override init()
```
```

--------------------------------

### init(pkcs12Url:importOptions:)

Source: https://github.com/emqx/cocoamqtt/wiki/SSLClientCertificate

Designated initializer that creates an SSLClientCertificate instance using a PKCS12 URL and import options.

```APIDOC
## init(pkcs12Url:importOptions:)

### Description
Designated init. Initializes an SSLClientCertificate using a PKCS12 URL and import options.

### Parameters
#### Path Parameters
- **pkcs12Url** (URL) - Required - URL to pkcs12 file containing private key and X.509 certificate (.p12)
- **importOptions** (CFDictionary) - Required - A dictionary containing import options. A kSecImportExportPassphrase entry is required at minimum. Only password-based PKCS12 blobs are currently supported. See **SecImportExport.h**
```

--------------------------------

### init(pkcs12Path:password:)

Source: https://github.com/emqx/cocoamqtt/wiki/SSLClientCertificate

Convenience initializer that creates an SSLClientCertificate instance using a PKCS12 file path and its password.

```APIDOC
## init(pkcs12Path:password:)

### Description
Convenience init. Initializes an SSLClientCertificate using a PKCS12 file path and password.

### Parameters
#### Path Parameters
- **pkcs12Path** (String) - Required - Path to pkcs12 file containing private key and X.509 certificate (.p12)
- **password** (String) - Required - File password, see **kSecImportExportPassphrase**
```

--------------------------------

### MqttSubscription Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/MqttSubscription

Initializes a new MqttSubscription with a specified topic.

```APIDOC
## init(topic:)

### Description
Initializes a new MqttSubscription with the given topic.

### Parameters
#### Path Parameters
- **topic** (String) - Required - The MQTT topic to subscribe to.
```

--------------------------------

### init(pkcs12Url:password:)

Source: https://github.com/emqx/cocoamqtt/wiki/SSLClientCertificate

Convenience initializer that creates an SSLClientCertificate instance using a PKCS12 URL and its password.

```APIDOC
## init(pkcs12Url:password:)

### Description
Convenience init. Initializes an SSLClientCertificate using a PKCS12 URL and password.

### Parameters
#### Path Parameters
- **pkcs12Url** (URL) - Required - URL to pkcs12 file containing private key and X.509 certificate (.p12)
- **password** (String) - Required - File password, see **kSecImportExportPassphrase**
```

--------------------------------

### MqttSubscription Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/MqttSubscription

Initializes a new MqttSubscription with a specified topic.

```swift
public init(topic: String) 

```

--------------------------------

### Get Certificate Chain from Trust

Source: https://github.com/emqx/cocoamqtt/wiki/SSLSecurity

Retrieves the certificate chain associated with a given SecTrust object. The chain is returned as an array of Data objects, each representing a certificate.

```swift
public func certificateChain(_ trust: SecTrust) -> [Data] 
```

--------------------------------

### Get Public Key Chain from Trust

Source: https://github.com/emqx/cocoamqtt/wiki/SSLSecurity

Extracts and returns the public keys from the certificate chain of a SecTrust object. This is useful for verifying the authenticity of the server's identity.

```swift
public func publicKeyChain(_ trust: SecTrust) -> [SecKey] 
```

--------------------------------

### CocoaMQTT Connect Method

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Initiates a connection to the MQTT broker.

```APIDOC
## connect()

### Description
Connect to MQTT broker.

### Method
`public func connect() -> Bool`

### Returns
`Bool` - Returns true if the connection attempt was successful, false otherwise.
```

--------------------------------

### connect

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTSocketProtocol

Establishes a connection to a specified host and port.

```APIDOC
## connect(toHost:​onPort:​)

### Description
Initiates a connection to the specified network host and port.

### Method Signature
`func connect(toHost host: String, onPort port: UInt16) throws

### Parameters
- `host` (String): The hostname or IP address of the server to connect to.
- `port` (UInt16): The port number on which the server is listening.

### Throws
An error if the connection fails.
```

--------------------------------

### connect()

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5

Initiates a connection to the MQTT broker. Returns a boolean indicating if the socket connection was successful, but not necessarily if the MQTT session is established.

```APIDOC
## connect()

### Description
Connect to MQTT broker.

### Method
`public func connect() -> Bool`

### Returns
- Bool: It indicates whether successfully calling socket connect function. Not yet established correct MQTT session
```

--------------------------------

### FoundationConnection Connect Method

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket_FoundationConnection

Initiates the connection to the WebSocket server.

```swift
public func connect() 
```

--------------------------------

### Connect to Host

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTSocket

Initiates a connection to a specified host and port. This method can throw an error.

```swift
public func connect(toHost host: String, onPort port: UInt16) throws 
```

--------------------------------

### Initialize with PKCS12 URL and Import Options

Source: https://github.com/emqx/cocoamqtt/wiki/SSLClientCertificate

Designated initializer for creating an SSLClientCertificate from a PKCS12 file URL and import options. A password in importOptions is mandatory.

```swift
public init(pkcs12Url: URL, importOptions: CFDictionary) throws 
```

--------------------------------

### Initialize with PKCS12 Path and Password

Source: https://github.com/emqx/cocoamqtt/wiki/SSLClientCertificate

Convenience initializer for creating an SSLClientCertificate from a PKCS12 file path and its password. Requires a valid file path and password.

```swift
public convenience init(pkcs12Path: String, password: String) throws 
```

--------------------------------

### connect

Source: https://github.com/emqx/cocoamqtt/wiki/FoundationStream

Establishes a connection to a specified URL and port with optional timeout, SSL settings, and a completion handler.

```APIDOC
## connect(url:port:timeout:ssl:completion:)

### Description
Establishes a connection to a specified URL and port with optional timeout, SSL settings, and a completion handler.

### Method
func connect(url: URL, port: Int, timeout: TimeInterval, ssl: SSLSettings, completion: @escaping ((Error?) -> Void))

### Parameters
- **url** (URL) - The URL to connect to.
- **port** (Int) - The port number to connect to.
- **timeout** (TimeInterval) - The connection timeout in seconds.
- **ssl** (SSLSettings) - SSL settings for the connection.
- **completion** (@escaping ((Error?) -> Void)) - A closure to be executed upon completion of the connection attempt, receiving an optional Error.
```

--------------------------------

### CocoaMQTT Connect Method

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Initiates a connection to the MQTT broker. Returns a boolean indicating success.

```swift
public func connect() -> Bool 
```

--------------------------------

### FoundationConnection Initializers

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket_FoundationConnection

Initializes a new FoundationConnection instance with a given URL and URLSessionConfiguration.

```APIDOC
## init(url:config:)

### Description
Initializes a new FoundationConnection instance.

### Parameters
- **url** (URL) - The URL for the WebSocket connection.
- **config** (URLSessionConfiguration) - The configuration for the URLSession.
```

--------------------------------

### WebSocket Convenience Initializer with URL and QoS

Source: https://github.com/emqx/cocoamqtt/wiki/WebSocket

A convenience initializer for creating a WebSocket instance with a URL, specifying the write queue Quality of Service, and optional protocols.

```swift
public convenience init(url: URL, writeQueueQOS: QualityOfService, protocols: [String]? = nil) 
```

--------------------------------

### Connect to Host and Port

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTSocketProtocol

Initiates a connection to a specified host and port. This method may throw an error if the connection fails.

```swift
func connect(toHost host: String, onPort port: UInt16) throws
```

--------------------------------

### Define SSLSettings Structure

Source: https://github.com/emqx/cocoamqtt/wiki/SSLSettings

Defines the main structure for SSL settings.

```swift
public struct SSLSettings 
```

--------------------------------

### Initialize with PKCS12 URL and Password

Source: https://github.com/emqx/cocoamqtt/wiki/SSLClientCertificate

Convenience initializer for creating an SSLClientCertificate from a PKCS12 file URL and its password. Requires a valid URL and password.

```swift
public convenience init(pkcs12Url: URL, password: String) throws 
```

--------------------------------

### Connect using MQTT 5.0 with CocoaMQTT

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Instantiate and connect a CocoaMQTT client using MQTT 5.0 protocol. Configure connection properties, username, password, will message, and keep-alive interval. Set the delegate for handling events.

```swift
///MQTT 5.0
let clientID = "CocoaMQTT-" + String(ProcessInfo().processIdentifier)
let mqtt5 = CocoaMQTT5(clientID: clientID, host: "broker.emqx.io", port: 1883)

let connectProperties = MqttConnectProperties()
connectProperties.topicAliasMaximum = 0
connectProperties.sessionExpiryInterval = 0
connectProperties.receiveMaximum = 100
connectProperties.maximumPacketSize = 500
mqtt5.connectProperties = connectProperties

mqtt5.username = "test"
mqtt5.password = "public"
mqtt5.willMessage = CocoaMQTTMessage(topic: "/will", string: "dieout")
mqtt5.keepAlive = 60
mqtt5.delegate = self
mqtt5.connect()
```

--------------------------------

### WebSocket Convenience Initializer with URL

Source: https://github.com/emqx/cocoamqtt/wiki/WebSocket

A convenience initializer for creating a WebSocket instance using a URL and optional protocols.

```swift
public convenience init(url: URL, protocols: [String]? = nil) 
```

--------------------------------

### CocoaMQTT5 Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5

Initializes a new CocoaMQTT5 client object with the specified client ID, host, port, and an optional socket.

```APIDOC
## init(clientID:host:port:socket:)

### Description
Initial client object.

### Parameters
- **clientID** (String) - Required - Client Identifier
- **host** (String) - Optional - The MQTT broker host domain or IP address. Default is "localhost"
- **port** (UInt16) - Optional - The MQTT service port of host. Default is 1883
- **socket** (CocoaMQTTSocketProtocol) - Optional - The socket to use for communication. Defaults to CocoaMQTTSocket().
```

--------------------------------

### Create MQTT 5.0 Instance over WebSocket

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Instantiate CocoaMQTT5 with WebSocket support for MQTT 5.0. Allows setting custom connect properties like topic alias maximum.

```swift
///MQTT 5.0
let websocket = CocoaMQTTWebSocket(uri: "/mqtt")
let mqtt5 = CocoaMQTT5(clientID: clientID, host: host, port: 8083, socket: websocket)
let connectProperties = MqttConnectProperties()
connectProperties.topicAliasMaximum = 0
// ...
mqtt5.connectProperties = connectProperties
// ...

_ = mqtt5.connect()
```

--------------------------------

### Connect to a URL

Source: https://github.com/emqx/cocoamqtt/wiki/FoundationStream

Establishes a connection to a specified URL, port, and timeout. Supports SSL and provides a completion handler for errors.

```swift
public func connect(url: URL, port: Int, timeout: TimeInterval, ssl: SSLSettings, completion: @escaping ((Error?) -> Void)) 

```

--------------------------------

### Connect to Host with Timeout

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTSocket

Initiates a connection to a specified host and port with a custom timeout. This method can throw an error.

```swift
public func connect(toHost host: String, onPort port: UInt16, withTimeout timeout: TimeInterval) throws 
```

--------------------------------

### init(identity:identityCertificate:)

Source: https://github.com/emqx/cocoamqtt/wiki/SSLClientCertificate

Designated initializer that creates an SSLClientCertificate instance using a SecIdentity and SecCertificate.

```APIDOC
## init(identity:identityCertificate:)

### Description
Designated init. For more information, see SSLSetCertificate() in Security/SecureTransport.h. Initializes an SSLClientCertificate using a SecIdentity and SecCertificate.

### Parameters
#### Path Parameters
- **identity** (SecIdentity) - Required - SecIdentityRef, see **kCFStreamSSLCertificates**
- **identityCertificate** (SecCertificate) - Required - CFArray of SecCertificateRefs, see **kCFStreamSSLCertificates**
```

--------------------------------

### Connect to WebSocket Server

Source: https://github.com/emqx/cocoamqtt/wiki/WSStream

Establishes a connection to a WebSocket server with specified parameters including URL, port, timeout, SSL settings, and a completion handler for connection status.

```swift
func connect(url: URL, port: Int, timeout: TimeInterval, ssl: SSLSettings, completion: @escaping ((Error?) -> Void))
```

--------------------------------

### DefaultConnectionBuilder Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket_DefaultConnectionBuilder

Initializes a new instance of DefaultConnectionBuilder.

```APIDOC
## init()

### Description
Initializes a new instance of the `DefaultConnectionBuilder`.

### Method
`init()`

### Parameters
None
```

--------------------------------

### Connect using MQTT 3.1.1 with CocoaMQTT

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Instantiate and connect a CocoaMQTT client using MQTT 3.1.1 protocol. Configure username, password, will message, and keep-alive interval. Set the delegate for handling events.

```swift
///MQTT 3.1.1
let clientID = "CocoaMQTT-" + String(ProcessInfo().processIdentifier)
let mqtt = CocoaMQTT(clientID: clientID, host: "broker.emqx.io", port: 1883)
mqtt.username = "test"
mqtt.password = "public"
mqtt.willMessage = CocoaMQTTMessage(topic: "/will", string: "dieout")
mqtt.keepAlive = 60
mqtt.delegate = self
mqtt.connect()
```

--------------------------------

### SSLCert Initializers

Source: https://github.com/emqx/cocoamqtt/wiki/SSLCert

Provides documentation for the initializers of the SSLCert class, allowing creation from certificate data or a public key.

```APIDOC
## init(data:)

### Description
Designated init for certificates.

### Method
`init(data: Data)`

### Parameters
- **data** (Data) - The binary data of the certificate.

### Returns
A representation security object to be used with.
```

```APIDOC
## init(key:)

### Description
Designated init for public keys.

### Method
`init(key: SecKey)`

### Parameters
- **key** (SecKey) - The public key to be used.

### Returns
A representation security object to be used with.
```

--------------------------------

### CocoaMQTT Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Initializes a CocoaMQTT client object with specified parameters. Defaults are provided for host and port.

```swift
public init(clientID: String, host: String = "localhost", port: UInt16 = 1883, socket: CocoaMQTTSocketProtocol = CocoaMQTTSocket()) 
```

--------------------------------

### Enable SSL Configuration

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTSocketProtocol

Configures whether SSL should be enabled for the socket connection.

```swift
var enableSSL: Bool 
```

--------------------------------

### Use Another Server Reason Code

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTCONNACKReasonCode

Indicates that the client should try connecting to a different server.

```swift
case useAnotherServer = 0x9C
```

--------------------------------

### Connect with Timeout

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTSocketProtocol

Initiates a connection to a specified host and port with a given timeout. This method may throw an error if the connection fails within the specified time.

```swift
func connect(toHost host: String, onPort port: UInt16, withTimeout timeout: TimeInterval) throws
```

--------------------------------

### buildConnection(forURL:withHeaders:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket_DefaultConnectionBuilder

Builds a CocoaMQTTWebSocketConnection for the given URL and headers.

```APIDOC
## buildConnection(forURL:withHeaders:)

### Description
Builds and returns a `CocoaMQTTWebSocketConnection` instance configured with the provided URL and headers.

### Method
`buildConnection(forURL: URL, withHeaders: [String: String]) throws -> CocoaMQTTWebSocketConnection`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Parameters
- **url** (URL) - Required - The URL for the WebSocket connection.
- **headers** ([String: String]) - Required - A dictionary of headers to include in the connection request.
```

--------------------------------

### FoundationConnection Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket_FoundationConnection

Initializes a new instance of FoundationConnection with a URL and URLSessionConfiguration.

```swift
public init(url: URL, config: URLSessionConfiguration) 
```

--------------------------------

### connect with timeout

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTSocketProtocol

Establishes a connection to a specified host and port with a specified timeout.

```APIDOC
## connect(toHost:​onPort:​withTimeout:​)

### Description
Initiates a connection to the specified network host and port, with a timeout for the connection attempt.

### Method Signature
`func connect(toHost host: String, onPort port: UInt16, withTimeout timeout: TimeInterval) throws

### Parameters
- `host` (String): The hostname or IP address of the server to connect to.
- `port` (UInt16): The port number on which the server is listening.
- `timeout` (TimeInterval): The maximum time in seconds to wait for the connection to establish.

### Throws
An error if the connection fails or times out.
```

--------------------------------

### Connect Method for CocoaMQTTWebSocketConnection

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocketConnection

Initiates the connection process for the WebSocket. Call this method to establish a connection.

```swift
func connect()

```

--------------------------------

### Handle MQTT Subscription Results

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Implement this delegate method to receive feedback on subscription attempts. It logs successful subscriptions and any topics that failed to subscribe to.

```swift
func mqtt(_ mqtt: CocoaMQTT, didSubscribeTopics success: NSDictionary, failed: [String]) {
        print("Subscribed to topics: \(success), failed to subscribe to: \(failed)")
    }
```

--------------------------------

### subscribe(_:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Subscribes to multiple MQTT topics by providing a list of topic-QoS tuples.

```APIDOC
## subscribe(_:)

### Description
Subscribe to a list of topics

### Method Signature
```swift
public func subscribe(_ topics: [(String, CocoaMQTTQoS)])
```

### Parameters
- **topics** (Array<(String, CocoaMQTTQoS)>) - A list of tuples, where each tuple contains a topic name/filter (String) and its corresponding Quality of Service level (CocoaMQTTQoS).
```

--------------------------------

### WebSocket Connect Method

Source: https://github.com/emqx/cocoamqtt/wiki/WebSocket

Initiates the connection to the WebSocket server on a background thread.

```swift
open func connect() 
```

--------------------------------

### CocoaMQTT5 SSLSettings Property

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5

Provides settings for SSL/TLS configuration.

```swift
public var sslSettings: [String: NSObject]? 
```

--------------------------------

### StarscreamConnection Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket_StarscreamConnection

Initializes a new StarscreamConnection instance with a given URLRequest.

```APIDOC
## init(request:)

### Description
Initializes a new StarscreamConnection instance with a given URLRequest.

### Parameters
#### Path Parameters
- **request** (URLRequest) - Required - The URLRequest to use for the WebSocket connection.
```

--------------------------------

### WebSocket Initializers

Source: https://github.com/emqx/cocoamqtt/wiki/WebSocket

These initializers are used to create a new WebSocket instance with different configuration options.

```APIDOC
## init(request:protocols:stream:)

### Description
Used for setting protocols when initializing the WebSocket.

### Parameters
- **request** (URLRequest) - The URL request object for the WebSocket connection.
- **protocols** ([String]?, optional) - An array of supported protocols.
- **stream** (WSStream, optional) - The stream implementation to use. Defaults to `FoundationStream()`.
```

```APIDOC
## init(url:protocols:)

### Description
Initializes a WebSocket connection to the specified URL.

### Parameters
- **url** (URL) - The URL for the WebSocket server.
- **protocols** ([String]?, optional) - An array of supported protocols.
```

```APIDOC
## init(url:writeQueueQOS:protocols:)

### Description
Initializes a WebSocket connection to the specified URL with a defined quality of service for the write queue.

### Parameters
- **url** (URL) - The URL for the WebSocket server.
- **writeQueueQOS** (QualityOfService) - The quality of service for the write queue.
- **protocols** ([String]?, optional) - An array of supported protocols.
```

--------------------------------

### WebSocket Initializer with Protocols

Source: https://github.com/emqx/cocoamqtt/wiki/WebSocket

Initializes a WebSocket instance with a URLRequest, optional protocols, and a WSStream implementation. Used for setting specific protocols during connection.

```swift
public init(request: URLRequest, protocols: [String]? = nil, stream: WSStream = FoundationStream()) 
```

--------------------------------

### Initialize CocoaMQTT5Message with String Payload

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5Message

Initializes a CocoaMQTT5Message with a topic, string payload, QoS, and retained flag.

```swift
public init(topic: String, string: String, qos: CocoaMQTTQoS = .qos1, retained: Bool = false) 
```

--------------------------------

### CocoaMQTTWebSocket Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket

Initializes a new instance of CocoaMQTTWebSocket. You can optionally provide a custom URI and a connection builder for advanced configuration.

```APIDOC
## init(uri:builder:)

### Description
Initializes a new instance of CocoaMQTTWebSocket.

### Parameters
- **uri** (String) - Optional: The WebSocket URI to connect to. Defaults to an empty string.
- **builder** (ConnectionBuilder) - Optional: A builder object for configuring the WebSocket connection. Defaults to `CocoaMQTTWebSocket.DefaultConnectionBuilder()`.
```

--------------------------------

### FoundationConnection Methods

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket_FoundationConnection

Provides methods for connecting, disconnecting, writing data, and handling WebSocket events.

```APIDOC
## connect()

### Description
Establishes the WebSocket connection.

### Method
`public func connect()`
```

```APIDOC
## disconnect()

### Description
Closes the WebSocket connection.

### Method
`public func disconnect()`
```

```APIDOC
## write(data:handler:)

### Description
Writes data to the WebSocket connection.

### Parameters
- **data** (Data) - The data to send.
- **handler** (@escaping (Error?) -> Void) - A closure to be called when the write operation completes.

### Method
`public func write(data: Data, handler: @escaping (Error?) -> Void)`
```

```APIDOC
## scheduleRead()

### Description
Schedules the reading of incoming data from the WebSocket.

### Method
`func scheduleRead()`
```

```APIDOC
## urlSession(_:task:didReceive:completionHandler:)

### Description
Delegate method called when the URLSession encounters an authentication challenge.

### Parameters
- **session** (URLSession) - The URL session.
- **task** (URLSessionTask) - The task that received the challenge.
- **challenge** (URLAuthenticationChallenge) - The authentication challenge.
- **completionHandler** (@escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) - The completion handler.

### Method
`public func urlSession(_ session: URLSession, task: URLSessionTask, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)`
```

```APIDOC
## urlSession(_:webSocketTask:didOpenWithProtocol:)

### Description
Delegate method called when the WebSocket connection is opened.

### Parameters
- **session** (URLSession) - The URL session.
- **webSocketTask** (URLSessionWebSocketTask) - The WebSocket task.
- **protocol** (String?) - The protocol used for the connection.

### Method
`public func urlSession(_ session: URLSession, webSocketTask: URLSessionWebSocketTask, didOpenWithProtocol protocol: String?)`
```

```APIDOC
## urlSession(_:webSocketTask:didCloseWith:reason:)

### Description
Delegate method called when the WebSocket connection is closed.

### Parameters
- **session** (URLSession) - The URL session.
- **webSocketTask** (URLSessionWebSocketTask) - The WebSocket task.
- **closeCode** (URLSessionWebSocketTask.CloseCode) - The close code.
- **reason** (Data?) - The reason for closing.

### Method
`public func urlSession(_ session: URLSession, webSocketTask: URLSessionWebSocketTask, didCloseWith closeCode: URLSessionWebSocketTask.CloseCode, reason: Data?)`
```

--------------------------------

### connect(timeout:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Establishes a connection to the MQTT broker with a specified timeout. Returns a boolean indicating the success of the socket connection, but not necessarily a fully established MQTT session.

```APIDOC
## connect(timeout:)

### Description
Connect to MQTT broker

### Method Signature
```swift
public func connect(timeout: TimeInterval) -> Bool
```

### Parameters
- **timeout** (TimeInterval) - Connect timeout

### Returns
- Bool: Indicates whether the socket connection was successful. Note: This does not guarantee a fully established MQTT session.
```

--------------------------------

### CocoaMQTT Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Initializes a new CocoaMQTT client object with the specified client ID, host, port, and an optional socket protocol.

```APIDOC
## init(clientID:host:port:socket:)

### Description
Initial client object.

### Parameters
- **clientID** (String) - Required - Client Identifier
- **host** (String) - Optional - The MQTT broker host domain or IP address. Default is "localhost"
- **port** (UInt16) - Optional - The MQTT service port of host. Default is 1883
- **socket** (CocoaMQTTSocketProtocol) - Optional - The socket protocol to use for communication.
```

--------------------------------

### Initialize SSLSecurity with Public Keys Option

Source: https://github.com/emqx/cocoamqtt/wiki/SSLSecurity

Initializes SSLSecurity, optionally using public keys for validation. This initializer is convenient for loading certificates from the main app bundle.

```swift
public convenience init(usePublicKeys: Bool = false) 
```

--------------------------------

### CocoaMQTTWebSocket Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket

Initializes a CocoaMQTTWebSocket instance with an optional URI and a ConnectionBuilder.

```swift
public init(uri: String = "", builder: ConnectionBuilder = CocoaMQTTWebSocket.DefaultConnectionBuilder()) 
```

--------------------------------

### CocoaMQTTWebSocket Methods

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket

Methods for managing the MQTT connection lifecycle, including setting delegates, connecting, and disconnecting.

```APIDOC
## Methods

### setDelegate(_:delegateQueue:)

#### Description
Sets the delegate object that will receive connection events and the dispatch queue on which delegate methods will be called.

#### Parameters
- **theDelegate** (CocoaMQTTSocketDelegate?) - The delegate object conforming to `CocoaMQTTSocketDelegate`.
- **delegateQueue** (DispatchQueue?) - The dispatch queue to use for delegate callbacks. If nil, callbacks are made on the main queue.
```

```APIDOC
### connect(toHost:onPort:)

#### Description
Attempts to establish a connection to the specified host and port.

#### Parameters
- **host** (String) - The hostname or IP address of the MQTT broker.
- **port** (UInt16) - The port number to connect to.

#### Throws
An error if the connection fails.
```

```APIDOC
### connect(toHost:onPort:withTimeout:)

#### Description
Attempts to establish a connection to the specified host and port with a specified timeout.

#### Parameters
- **host** (String) - The hostname or IP address of the MQTT broker.
- **port** (UInt16) - The port number to connect to.
- **timeout** (TimeInterval) - The maximum time in seconds to wait for the connection to establish.

#### Throws
An error if the connection fails or times out.
```

```APIDOC
### disconnect()

#### Description
Closes the current MQTT connection gracefully.
```

```APIDOC
### readData(toLength:withTimeout:tag:)

#### Description
Initiates reading a specific number of bytes from the connection with a timeout.

#### Parameters
- **length** (UInt) - The number of bytes to read.
- **timeout** (TimeInterval) - The maximum time in seconds to wait for the data.
- **tag** (Int) - An identifier for this read operation.
```

```APIDOC
### write(_:withTimeout:tag:)

#### Description
Writes data to the connection with a specified timeout.

#### Parameters
- **data** (Data) - The data to be written.
- **timeout** (TimeInterval) - The maximum time in seconds to wait for the write operation to complete.
- **tag** (Int) - An identifier for this write operation.
```

--------------------------------

### Import CocoaMQTT and Starscream

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Import necessary libraries for WebSocket support in CocoaMQTT. Required when integrating via Swift Package Manager.

```swift
import CocoaMQTT
import CocoaMQTTWebSocket
import Starscream
```

--------------------------------

### publish(_:withString:qos:DUP:retained:properties:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5

Publishes a string message to a specified topic with configurable QoS, DUP flag, retained flag, and properties.

```APIDOC
## publish(_:withString:qos:DUP:retained:properties:)

### Description
Publish a message to broker

### Method
`@discardableResult public func publish(_ topic: String, withString string: String, qos: CocoaMQTTQoS = .qos1, DUP: Bool = false, retained: Bool = false, properties: MqttPublishProperties) -> Int`

### Parameters
- topic (String): Topic Name. It can not contain '\#' or '+' wildcards.
- string (String): Payload string.
- qos (CocoaMQTTQoS): Qos. Default is Qos1.
- retained (Bool): Retained flag. Mark this message as a retained message. Default is false.

### Returns
- 0 will be returned, if the message's qos is qos0.
- 1-65535 will be returned, if the messages's qos is qos1/qos2.
- -1 will be returned, if the messages queue is full.
```

--------------------------------

### SSL Use Flag

Source: https://github.com/emqx/cocoamqtt/wiki/SSLSettings

Boolean property to indicate whether SSL should be used for the connection.

```swift
public let useSSL: Bool
```

--------------------------------

### publish(_:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Publishes a pre-constructed CocoaMQTTMessage object to the broker.

```APIDOC
## publish(_:)

### Description
Publish a message to broker

### Method Signature
```swift
@discardableResult
public func publish(_ message: CocoaMQTTMessage) -> Int
```

### Parameters
- **message** (CocoaMQTTMessage) - The message object to publish.

### Returns
- `0` if the message's QoS is `qos0`.
- `1-65535` if the message's QoS is `qos1` or `qos2`.
- `-1` if the message queue is full.
```

--------------------------------

### Connect to MQTT Broker

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Initiates a connection to the MQTT broker with a specified timeout. Returns a boolean indicating the success of the socket connection, but not necessarily the establishment of a correct MQTT session.

```swift
public func connect(timeout: TimeInterval) -> Bool 
```

--------------------------------

### subscribe(_:qos:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Subscribes to a single MQTT topic with a specified Quality of Service (QoS) level.

```APIDOC
## subscribe(_:qos:)

### Description
Subscribe to a MQTT topic

### Method Signature
```swift
public func subscribe(_ topic: String, qos: CocoaMQTTQoS = .qos1)
```

### Parameters
- **topic** (String) - The topic name or topic filter to subscribe to.
- **qos** (CocoaMQTTQoS) - The desired Quality of Service level. Defaults to `.qos1`.
```

--------------------------------

### buildConnection(forURL:withHeaders:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocketConnectionBuilder

Builds a WebSocket connection for a given URL and headers.

```APIDOC
## buildConnection(forURL:withHeaders:)

### Description
Builds a WebSocket connection for a given URL and headers.

### Method
func buildConnection(forURL url: URL, withHeaders headers: [String: String]) throws -> CocoaMQTTWebSocketConnection
```

--------------------------------

### mqtt5(_:didStateChangeTo:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5Delegate

Called when the MQTT5 client's connection state changes.

```APIDOC
## mqtt5(_:didStateChangeTo:)

### Description
Called when the MQTT5 client's connection state changes.

### Method Signature
```swift
@objc optional func mqtt5(_ mqtt5: CocoaMQTT5, didStateChangeTo state: CocoaMQTTConnState)
```

### Parameters
- `mqtt5` (CocoaMQTT5): The MQTT5 client instance.
- `state` (CocoaMQTTConnState): The new connection state.
```

--------------------------------

### CocoaMQTTMessage Initializers

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTMessage

Initializers for creating a CocoaMQTTMessage object.

```APIDOC
## init(topic:string:qos:retained:)

### Description
Initializes a new MQTT message with a topic, string payload, QoS level, and retained flag.

### Parameters
- **topic** (String) - The MQTT topic for the message.
- **string** (String) - The message payload as a string.
- **qos** (CocoaMQTTQoS) - The Quality of Service level for the message. Defaults to .qos1.
- **retained** (Bool) - Whether the message should be retained by the broker. Defaults to false.

### Method
`init`
```

```APIDOC
## init(topic:payload:qos:retained:)

### Description
Initializes a new MQTT message with a topic, byte array payload, QoS level, and retained flag.

### Parameters
- **topic** (String) - The MQTT topic for the message.
- **payload** ([UInt8]) - The message payload as a byte array.
- **qos** (CocoaMQTTQoS) - The Quality of Service level for the message. Defaults to .qos1.
- **retained** (Bool) - Whether the message should be retained by the broker. Defaults to false.

### Method
`init`
```

--------------------------------

### MqttSubscription Topic Property

Source: https://github.com/emqx/cocoamqtt/wiki/MqttSubscription

Represents the MQTT topic for the subscription.

```swift
public var topic: String

```

--------------------------------

### Subscribe to Multiple Topics

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5

Subscribes to a list of MQTT topics, each with its own QoS level.

```swift
public func subscribe(_ topics: [MqttSubscription]) 
```

--------------------------------

### publish(_:withString:qos:retained:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Publishes a string message to a specified topic with configurable Quality of Service (QoS) and retained flag.

```APIDOC
## publish(_:withString:qos:retained:)

### Description
Publish a message to broker

### Method Signature
```swift
@discardableResult
public func publish(_ topic: String, withString string: String, qos: CocoaMQTTQoS = .qos1, retained: Bool = false) -> Int
```

### Parameters
- **topic** (String) - Topic Name. It can not contain '\#' or '+' wildcards.
- **string** (String) - Payload string.
- **qos** (CocoaMQTTQoS) - Quality of Service level. Defaults to `.qos1`.
- **retained** (Bool) - Retained flag. Set to true to mark this message as a retained message. Defaults to `false`.

### Returns
- `0` if the message's QoS is `qos0`.
- `1-65535` if the message's QoS is `qos1` or `qos2`.
- `-1` if the message queue is full.
```

--------------------------------

### Initialize CocoaMQTT5Message with Byte Array Payload

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5Message

Initializes a CocoaMQTT5Message with a topic, byte array payload, QoS, and retained flag.

```swift
public init(topic: String, payload: [UInt8], qos: CocoaMQTTQoS = .qos1, retained: Bool = false) 
```

--------------------------------

### CocoaMQTTSocket Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTSocket

Initializes a new instance of the CocoaMQTTSocket class.

```APIDOC
## init()

### Description
Initializes a new instance of the CocoaMQTTSocket class.

### Method
`init()`
```

--------------------------------

### mqtt5(_:didStateChangeTo:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5Delegate

Called when the MQTT5 client's connection state changes. Provides the new connection state.

```swift
@objc optional func mqtt5(_ mqtt5: CocoaMQTT5, didStateChangeTo state: CocoaMQTTConnState)
```

--------------------------------

### Handle Incoming Messages with Closures

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Set a closure to handle incoming MQTT messages, providing the client, message, and message ID.

```swift
mqtt.didReceiveMessage = { mqtt, message, id in
    print("Message received in topic \(message.topic) with payload \(message.string!)")
}
```

--------------------------------

### Default Write Implementations

Source: https://github.com/emqx/cocoamqtt/wiki/WebSocketClient

Provides default implementations for writing string, data, ping, pong, and disconnecting.

```swift
public func write(string: String) 

```

```swift
public func write(data: Data) 

```

```swift
public func write(ping: Data) 

```

```swift
public func write(pong: Data) 

```

```swift
public func disconnect() 

```

--------------------------------

### CocoaMQTT5Message Initializers

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5Message

Initializers for creating a CocoaMQTT5Message instance. You can initialize with a topic and a string payload, or a topic and a byte array payload.

```APIDOC
## Initializers

### `init(topic:string:qos:retained:)`

```swift
public init(topic: String, string: String, qos: CocoaMQTTQoS = .qos1, retained: Bool = false)
```

### `init(topic:payload:qos:retained:)`

```swift
public init(topic: String, payload: [UInt8], qos: CocoaMQTTQoS = .qos1, retained: Bool = false)
```
```

--------------------------------

### Build WebSocket Connection

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocketConnectionBuilder

Implement this method to construct a WebSocket connection for a given URL and headers.

```swift
func buildConnection(forURL url: URL, withHeaders headers: [String: String]) throws -> CocoaMQTTWebSocketConnection

```

--------------------------------

### Connect with Custom Headers and SSL

Source: https://github.com/emqx/cocoamqtt/blob/master/README.md

Configure WebSocket connection with custom HTTP headers and enable SSL. Useful for authentication or secure connections.

```swift
let websocket = CocoaMQTTWebSocket(uri: "/mqtt")
websocket.headers = [
            "x-api-key": "value"
        ]
        websocket.enableSSL = true

let mqtt = CocoaMQTT(clientID: clientID, host: host, port: 8083, socket: websocket)

// ...

_ = mqtt.connect()
```

--------------------------------

### Subscribe to Multiple Topics

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT

Subscribes to a list of MQTT topics, each with its own QoS level. The topics are provided as an array of tuples.

```swift
public func subscribe(_ topics: [(String, CocoaMQTTQoS)]) 
```

--------------------------------

### mqtt(_:didStateChangeTo:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTDelegate

Called when the MQTT client's connection state changes.

```APIDOC
## mqtt(_:didStateChangeTo:)

### Description
Called when the MQTT client's connection state changes.

### Signature
```swift
@objc optional func mqtt(_ mqtt: CocoaMQTT, didStateChangeTo state: CocoaMQTTConnState)
```
```

--------------------------------

### StarscreamConnection Initializer

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket_StarscreamConnection

Initializes a new StarscreamConnection instance with a given URLRequest. This is used to establish the WebSocket connection.

```swift
public init(request: URLRequest) 
```

--------------------------------

### Handle WebSocket Connection

Source: https://github.com/emqx/cocoamqtt/wiki/WebSocketDelegate

Implement this method to be notified when a WebSocket connection is successfully established.

```swift
func websocketDidConnect(socket: WebSocketClient)
```

--------------------------------

### subscribe(_:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5

Subscribes to a list of topics with their respective QoS levels.

```APIDOC
## subscribe(_:)

### Description
Subscribe to a list of topics.

### Method
`public func subscribe(_ topics: [MqttSubscription])`

### Parameters
- topics ([MqttSubscription]): A list of subscriptions, where each subscription is a tuple of (Topic Name or Topic Filter, Qos).
```

--------------------------------

### mqttDidPing(_:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTDelegate

Called when a PINGREQ is sent to the MQTT broker.

```APIDOC
## mqttDidPing(_:)

### Description
Called when a PINGREQ is sent to the MQTT broker.

### Signature
```swift
func mqttDidPing(_ mqtt: CocoaMQTT)
```
```

--------------------------------

### publish(_:DUP:retained:properties:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTT5

Publishes a CocoaMQTT5Message to a specified topic with configurable DUP flag, retained flag, and properties.

```APIDOC
## publish(_:DUP:retained:properties:)

### Description
Publish a message to broker

### Method
`@discardableResult public func publish(_ message: CocoaMQTT5Message, DUP: Bool = false, retained: Bool = false, properties: MqttPublishProperties) -> Int`

### Parameters
- message (CocoaMQTT5Message): The message to publish.
- DUP (Bool): The DUP flag.
- retained (Bool): The retained flag.
- properties (MqttPublishProperties): Publish properties.
```

--------------------------------

### Reason String Property

Source: https://github.com/emqx/cocoamqtt/wiki/MqttAuthProperties

Provides a reason string associated with the authentication. This property is optional.

```swift
public var reasonString: String?
```

--------------------------------

### Initialize SSLCert with SecKey

Source: https://github.com/emqx/cocoamqtt/wiki/SSLCert

Initializes an SSLCert object using a public key. This is the designated initializer for public keys.

```swift
public init(key: SecKey) 
```

--------------------------------

### mqtt(_:didStateChangeTo:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTDelegate

Called when the MQTT client's connection state changes.

```swift
@objc optional func mqtt(_ mqtt: CocoaMQTT, didStateChangeTo state: CocoaMQTTConnState)
```

--------------------------------

### CocoaMQTTWebSocketConnectionDelegate Methods

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTWebSocket

Delegate methods for handling WebSocket connection events.

```APIDOC
## Delegate Methods

### connection(_:didReceive:completionHandler:)

#### Description
Called when the connection receives an SSL trust object. This method is part of the `CocoaMQTTWebSocketConnectionDelegate` protocol and is used for SSL certificate validation.

#### Parameters
- **conn** (CocoaMQTTWebSocketConnection) - The connection object.
- **trust** (SecTrust) - The trust object representing the server's certificate.
- **completionHandler** (@escaping (Bool) -> Swift.Void) - A closure to be called with a boolean indicating whether the trust is valid.
```

```APIDOC
### connectionOpened(_:)

#### Description
Called when the WebSocket connection is successfully opened.

#### Parameters
- **conn** (CocoaMQTTWebSocketConnection) - The connection object.
```

```APIDOC
### connectionClosed(_:withError:)

#### Description
Called when the WebSocket connection is closed, either intentionally or due to an error.

#### Parameters
- **conn** (CocoaMQTTWebSocketConnection) - The connection object.
- **error** (Error?) - An optional error object if the connection was closed due to an error.
```

```APIDOC
### connection(_:receivedString:)

#### Description
Called when the connection receives a string message.

#### Parameters
- **conn** (CocoaMQTTWebSocketConnection) - The connection object.
- **string** (String) - The received string message.
```

```APIDOC
### connection(_:receivedData:)

#### Description
Called when the connection receives a data message.

#### Parameters
- **conn** (CocoaMQTTWebSocketConnection) - The connection object.
- **data** (Data) - The received data message.
```

--------------------------------

### mqtt(_:didReceive:completionHandler:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTDelegate

Optional method to manually validate SSL/TLS server certificates. Called if `allowUntrustCACertificate` is enabled.

```swift
@objc optional func mqtt(_ mqtt: CocoaMQTT, didReceive trust: SecTrust, completionHandler: @escaping (Bool) -> Void)
```

--------------------------------

### mqtt(_:didPublishAck:)

Source: https://github.com/emqx/cocoamqtt/wiki/CocoaMQTTDelegate

Called when a publish acknowledgment (PUBACK) is received from the MQTT broker.

```APIDOC
## mqtt(_:didPublishAck:)

### Description
Called when a publish acknowledgment (PUBACK) is received from the MQTT broker.

### Signature
```swift
func mqtt(_ mqtt: CocoaMQTT, didPublishAck id: UInt16)
```
```