### Start Local Development Server

Source: https://github.com/gojek/courier-android/blob/main/docs/README.md

Starts a local development server for live preview. Changes are reflected without server restart.

```bash
yarn start
```

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

### Apply Code Formatting with Spotless

Source: https://github.com/gojek/courier-android/blob/main/CONTRIBUTING.md

Run this Gradle task to automatically format your Kotlin code according to the project's style guide. This should be done before submitting a pull request.

```bash
./gradlew spotlessApply
```

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

### Install Dependencies

Source: https://github.com/gojek/courier-android/blob/main/docs/README.md

Installs project dependencies using Yarn.

```bash
yarn
```

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

### Configure and Connect MqttClient

Source: https://github.com/gojek/courier-android/blob/main/README.md

Set up MqttConnectOptions with server details, client ID, authentication, and keep-alive settings. Then, establish a connection to the MQTT broker using the configured options.

```kotlin
val connectOptions = MqttConnectOptions(
    serverUris = listOf(ServerUri(SERVER_URI, SERVER_PORT)),
    clientId = clientId,
    username = username,
    keepAlive = KeepAlive(
        timeSeconds = keepAliveSeconds
    ),
    isCleanSession = cleanSessionFlag,
    password = password
)

mqttClient.connect(connectOptions)
```

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

### Courier Client Initialization

Source: https://github.com/gojek/courier-android/blob/main/README.md

Demonstrates how to initialize the Courier client with MQTT client, stream adapters, and message adapters.

```APIDOC
## Courier Client Initialization

### Description
Initializes the Courier client with necessary configurations including the MQTT client, stream adapter factories, and message adapter factories.

### Code
```kotlin
val mqttClient = MqttClientFactory.create(
    context = context,
    mqttConfiguration = MqttV3Configuration(
        authenticator = authenticator
    )
)

val courierConfiguration = Courier.Configuration(
    client = mqttClient,
    streamAdapterFactories = listOf(RxJava2StreamAdapterFactory()),
    messageAdapterFactories = listOf(GsonMessageAdapter.Factory())
)

val courier = Courier(courierConfiguration)

val messageService = courier.create<MessageService>()
```
```

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

### Create MqttClient Instance

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/ConnectionSetup.md

Instantiate an MqttClient using the MqttClientFactory. Requires the application context and MQTT configuration.

```kotlin
val mqttClient = MqttClientFactory.create(
    context = context,
    mqttConfiguration = mqttConfiguration
)
```

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

### Connect using MqttClient

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/ConnectionSetup.md

Establish a connection to the MQTT broker using MqttClient. Configure server URIs, client ID, credentials, keep-alive interval, clean session flag, and ALPN protocols.

```kotlin
val alpnProtocol = "mqtt"
val connectOptions = MqttConnectOptions.Builder()
              .serverUris(listof(ServerUri(SERVER_URI, SERVER_PORT)))
              .clientId(clientId)
              .userName(username)
              .password(password)
              .keepAlive(KeepAlive(timeSeconds = keepAliveSeconds))
              .cleanSession(cleanSessionFlag)
              .alpnProtocols(listOf(Protocol(alpnProtocol)))
              .build()

mqttClient.connect(connectOptions)
```

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

### Create Courier Implementation

Source: https://github.com/gojek/courier-android/blob/main/README.md

Instantiate MqttClient and configure Courier with necessary adapters. Then, create an implementation of your message service interface using the Courier instance.

```kotlin
val mqttClient = MqttClientFactory.create(
    context = context,
    mqttConfiguration = MqttV3Configuration(
        authenticator = authenticator
    )
)

val courierConfiguration = Courier.Configuration(
    client = mqttClient,
    streamAdapterFactories = listOf(RxJava2StreamAdapterFactory()),
    messageAdapterFactories = listOf(GsonMessageAdapter.Factory())
)

val courier = Courier(courierConfiguration)

val messageService = courier.create<MessageService>()
```

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

### Send and Receive Messages using MqttClient

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SendReceiveMessage.md

Shows how to send a message with a specific QoS level and add a listener for incoming messages on a given topic using the MqttClient. Only subscribed topics can receive messages.

```kotlin
mqttClient.send(message, topic, QoS.TWO)

mqttClient.addMessageListener(topic, object : MessageListener {
    override fun onMessageReceived(mqttMessage: MqttMessage) {
        print(mqttMessage)
    }
})
```

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

### Build Static Website

Source: https://github.com/gojek/courier-android/blob/main/docs/README.md

Generates static website content into the 'build' directory for hosting.

```bash
yarn build
```

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

### Create MqttClient

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/ConnectionSetup.md

Instantiate an MqttClient using the MqttClientFactory. This client is essential for establishing and managing MQTT connections.

```APIDOC
## Create MqttClient

### Description
An instance of `MqttClient` needs to be created in order to establish a Courier connection.

### Code Example
```kotlin
val mqttClient = MqttClientFactory.create(
    context = context,
    mqttConfiguration = mqttConfiguration
)
```
```

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

### Compile Project with Gradle

Source: https://github.com/gojek/courier-android/blob/main/CONTRIBUTING.md

Ensure your code compiles successfully by running this Gradle command. This is a prerequisite before submitting changes.

```bash
./gradlew assembleDebug
```

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

### Send/Receive using MqttClient

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SendReceiveMessage.md

Illustrates sending messages and setting up listeners for receiving messages using the MqttClient.

```APIDOC
## Send/Receive using MqttClient

### Description
This section explains how to send messages directly using `MqttClient` and how to register a listener for receiving messages on a specific topic.

### Sending a Message
```kotlin
mqttClient.send(message, topic, QoS.TWO)
```

### Receiving Messages
```kotlin
mqttClient.addMessageListener(topic, object : MessageListener {
    override fun onMessageReceived(mqttMessage: MqttMessage) {
        print(mqttMessage)
    }
})
```

### Parameters
#### Send Method Parameters
- **message** (Message) - Required - The message to send.
- **topic** (String) - Required - The topic to send the message to.
- **qos** (QoS) - Required - The Quality of Service level.

#### Add Message Listener Parameters
- **topic** (String) - Required - The topic to listen for messages on.
- **listener** (MessageListener) - Required - The listener to be invoked when a message is received.
```

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

### Send and Receive Messages using Service Interface

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SendReceiveMessage.md

Demonstrates how to send a message and set up a listener for receiving messages using the defined MessageService. Ensure the topic and identifier match the interface definition.

```kotlin
messageService.send("user-id", message)

messageService.receive("user-id") { message ->
    print(message)
}
```

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

### Subscribe/Unsubscribe through MqttClient

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SubscribeUnsubscribe.md

Demonstrates how to subscribe and unsubscribe to topics directly using the MqttClient.

```APIDOC
## Subscribe to topics via MqttClient

### Description
Subscribes to one or more topics with specified Quality of Service (QoS) levels using the MqttClient.

### Method
subscribe

### Endpoint
N/A (Method-based subscription)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```kotlin
mqttClient.subscribe("topic1" to QoS.ZERO, "topic2" to QoS.ONE)
```

### Response
#### Success Response (200)
Indicates successful subscription.

#### Response Example
None

## Unsubscribe from topics via MqttClient

### Description
Unsubscribes from one or more specified topics using the MqttClient.

### Method
unsubscribe

### Endpoint
N/A (Method-based unsubscription)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```kotlin
mqttClient.unsubscribe("topic1", "topic2")
```

### Response
#### Success Response (200)
Indicates successful unsubscription.

#### Response Example
None
```

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

### Subscribe and Unsubscribe using MqttClient

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SubscribeUnsubscribe.md

Provides a direct way to subscribe and unsubscribe from topics using the MqttClient. This method is useful for lower-level control over MQTT connections.

```kotlin
mqttClient.subscribe("topic1" to QoS.ZERO, "topic2" to QoS.ONE)

mqttClient.unsubscribe("topic1", "topic2")
```

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

### Deploy Website (No SSH)

Source: https://github.com/gojek/courier-android/blob/main/docs/README.md

Deploys the website without SSH, requiring a GitHub username for deployment.

```bash
GIT_USER=<Your GitHub username> yarn deploy
```

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

### Connect using MqttClient

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/ConnectionSetup.md

Connect to the MQTT broker using the MqttClient with detailed connection options, including server URIs, client ID, authentication, keep-alive interval, clean session flag, and ALPN protocols.

```APIDOC
## Connect using MqttClient

### Description
Establishes a connection to the MQTT broker using the `MqttClient` with configurable `MqttConnectOptions`.

### Code Example
```kotlin
val alpnProtocol = "mqtt"
val connectOptions = MqttConnectOptions.Builder()
              .serverUris(listof(ServerUri(SERVER_URI, SERVER_PORT)))
              .clientId(clientId)
              .userName(username)
              .password(password)
              .keepAlive(KeepAlive(timeSeconds = keepAliveSeconds))
              .cleanSession(cleanSessionFlag)
              .alpnProtocols(listOf(Protocol(alpnProtocol)))
              .build()

mqttClient.connect(connectOptions)
```
```

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

### Deploy Website (SSH)

Source: https://github.com/gojek/courier-android/blob/main/docs/README.md

Deploys the website using SSH, typically for pushing to a 'gh-pages' branch.

```bash
USE_SSH=true yarn deploy
```

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

### Create WorkManagerPingSender

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/PingSender.md

Instantiate the MQTT ping sender using the WorkPingSenderFactory. This method is suitable for background connection maintenance and requires specific WorkManager configurations.

```kotlin
pingSender = WorkPingSenderFactory.createMqttPingSender(
                context, workManagerPingSenderConfig
            )
```

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

### Use MessageService to Subscribe and Unsubscribe

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SubscribeUnsubscribe.md

Demonstrates how to use the MessageService interface to subscribe to single and multiple topics, and to unsubscribe. Ensure message formats are consistent or handled by an adapter when using subscribeMultiple.

```kotlin
messageService.subscribe("user-id").subscribe { message ->
    print(message)
}

messageService.subscribeMultiple(mapOf("topic1" to QoS.ONE, "topic2" to QoS.TWO)).subscribe { message ->
    print(message)
}

messageService.unsubscribe("user-id")
```

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

### Publish Artifacts Locally

Source: https://github.com/gojek/courier-android/blob/main/CONTRIBUTING.md

Use this script to publish artifacts to your local Maven repository. This is useful for local testing of your changes.

```bash
./scripts/publishMavenLocal.sh
```

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

### Send/Receive using Service Interface

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SendReceiveMessage.md

Demonstrates sending and receiving messages using the MessageService interface, which handles topic subscriptions and message routing.

```APIDOC
## Send/Receive using Service Interface

### Description
This section details how to send and receive messages using the `MessageService` interface. It leverages annotations like `@Receive` and `@Send` to define message handling logic.

### Interface Definition
```kotlin
interface MessageService {
	@Receive(topic = "topic/{id}/receive")
	fun receive(@Path("id") identifier: String): Observable<Message>
	
	@Send(topic = "topic/{id}/send", qos = QoS.TWO)
	fun send(@Path("id") identifier: String, @Data message: Message)
}
```

### Usage Examples
```kotlin
// Sending a message
messageService.send("user-id", message)

// Receiving messages
messageService.receive("user-id") { message ->
    print(message)
}
```

### Parameters
#### Path Parameters
- **id** (String) - Required - Identifier for the topic.

#### Request Body
- **message** (Message) - Required - The message object to be sent.
```

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

### Create AlarmPingSender

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/PingSender.md

Instantiate the MQTT ping sender using the AlarmPingSenderFactory. This is suitable for background connection maintenance, but be aware of the permission requirements for exact alarms on newer Android versions.

```kotlin
pingSender = AlarmPingSenderFactory.createMqttPingSender(
                context, alarmPingSenderConfig
            )
```

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

### Add MQTT Chuck Dependency

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/MqttChuck.md

Add the MQTT Chuck dependency to your project's build.gradle file.

```kotlin
dependencies {
    implementation "com.gojek.courier:chuck-mqtt:x.y.z"
}
```

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

### Create Courier Service Implementation

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/CourierService.md

Use Courier to create an implementation of a service interface by configuring the Courier client, stream adapter factories, and message adapter factories. The create method generates the service instance.

```kotlin
val courierConfiguration = Courier.Configuration(
    client = mqttClient,
    streamAdapterFactories = listOf(RxJava2StreamAdapterFactory()),
    messageAdapterFactories = listOf(GsonMessageAdapter.Factory())
)

val courier = Courier(courierConfiguration)

val messageService = courier.create<MessageService>()
```

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

### Create HttpAuthenticator Instance

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/Authenticator.md

Instantiate HttpAuthenticator using the factory class, providing necessary dependencies like Retrofit, API URL, and event/retry handlers.

```kotlin
httpAuthenticator = HttpAuthenticatorFactory.create(
            retrofit = retrofit,
            apiUrl = TOKEN_AUTH_API,
            responseHandler = responseHandler,
            eventHandler = eventHandler,
            authRetryPolicy = authRetryPolicy
        )
```

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

### Create TimerPingSender

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/PingSender.md

Create an instance of the TimerPingSender using its factory class. This sender is designed for keeping MQTT connections alive only when the application is actively in the foreground.

```kotlin
pingSender = TimerPingSenderFactory.create()
```

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

### Subscribe/Unsubscribe through Service Interface

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SubscribeUnsubscribe.md

Demonstrates how to subscribe and unsubscribe to topics using the MessageService interface.

```APIDOC
## Subscribe to a topic via Service Interface

### Description
Subscribes to a specific topic identified by an ID.

### Method
@Subscribe

### Endpoint
topic/{id}/receive

### Parameters
#### Path Parameters
- **id** (string) - Required - The identifier for the topic.

#### Query Parameters
None

#### Request Body
None

### Request Example
```kotlin
messageService.subscribe("user-id")
```

### Response
#### Success Response (200)
- **message** (Message) - The received message.

#### Response Example
```json
{
  "message": "Received message content"
}
```

## Subscribe to multiple topics via Service Interface

### Description
Subscribes to multiple topics with specified Quality of Service (QoS) levels.

### Method
@SubscribeMultiple

### Endpoint
N/A (Method-based subscription)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
- **topics** (Map<String, QoS>) - Required - A map where keys are topic names and values are their QoS levels.

### Request Example
```kotlin
messageService.subscribeMultiple(mapOf("topic1" to QoS.ONE, "topic2" to QoS.TWO))
```

### Response
#### Success Response (200)
- **message** (Message) - The received message.

#### Response Example
```json
{
  "message": "Received message content"
}
```

## Unsubscribe from a topic via Service Interface

### Description
Unsubscribes from a specific topic identified by an ID.

### Method
@Unsubscribe

### Endpoint
topic/{id}/receive

### Parameters
#### Path Parameters
- **id** (string) - Required - The identifier for the topic to unsubscribe from.

#### Query Parameters
None

#### Request Body
None

### Request Example
```kotlin
messageService.unsubscribe("user-id")
```

### Response
#### Success Response (200)
No content is typically returned upon successful unsubscription.

#### Response Example
None
```

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

### Apply Kotlin Style to IntelliJ IDEA

Source: https://github.com/gojek/courier-android/blob/main/CONTRIBUTING.md

Generate IntelliJ IDEA/Android Studio Kotlin style files to ensure your IDE adheres to the project's coding rules. This helps maintain consistent code formatting.

```bash
./gradlew ktlintApplyToIdea
```

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

### Add Courier Dependencies

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/Installation.md

Declare the Courier library and its adapters in your app's build.gradle file. Ensure you use the latest version available on Maven Central.

```kotlin
repositories {
    mavenCentral()
}

dependencies {
    implementation "com.gojek.courier:courier:x.y.z"

    implementation "com.gojek.courier:courier-message-adapter-gson:x.y.z"
    implementation "com.gojek.courier:courier-stream-adapter-rxjava2:x.y.z"
}
```

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

### Generate API Dumps with Binary Compatibility Validator

Source: https://github.com/gojek/courier-android/blob/main/CONTRIBUTING.md

If your changes affect public APIs, use this command to generate updated API dumps. Commit these changes to track binary compatibility.

```bash
./gradlew apiDump
```

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

### Set UserProperties in MqttConnectionOptions

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/NonStandardOptions.md

Use the userProperties builder to include custom key-value pairs in the CONNECT packet. This is a non-standard option for MQTT v3.1.1 and requires broker support.

```kotlin
val connectOptions = MqttConnectOptions.Builder()
              .serverUris(listOf(ServerUri(SERVER_URI, SERVER_PORT)))
              .clientId(clientId)
              ...
              .userProperties(
                  userProperties = mapOf(
                    "key1" to "value1",
                    "key2" to "value2"
                  )
              )
              .build()

mqttClient.connect(connectOptions)
```

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

### Set UserProperties in MqttConnectionOptions (Kotlin)

Source: https://github.com/gojek/courier-android/blob/main/README.md

Use this option to send user-properties in the CONNECT packet for MQTT v3.1.1. Note that this is a non-standard option and requires broker support.

```kotlin
val connectOptions = MqttConnectOptions(
    serverUris = listOf(ServerUri(SERVER_URI, SERVER_PORT)),
    clientId = clientId,
    ...
    userPropertiesMap = mapOf(
                "key1" to "value1",
                "key2" to "value2"
    )
)

mqttClient.connect(connectOptions)
```

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

### Enable MQTT Chuck Interceptor

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/MqttChuck.md

Pass the MqttChuckInterceptor to your MqttConfiguration to enable MQTT Chuck for your courier connection.

```kotlin
mqttConfiguration = MqttV3Configuration(
    mqttInterceptorList = listOf(MqttChuckInterceptor(context, mqttChuckConfig))
)
```

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

### Send and Receive Messages

Source: https://github.com/gojek/courier-android/blob/main/README.md

Utilize the message service to send messages to a specified topic and receive messages. The receive function can be used with a callback to process incoming messages.

```kotlin
messageService.send("user-id", message)
messageService.receive("user-id") {
    print(message)
}
```

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

### Add TimerPingSender Dependency

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/PingSender.md

Add this dependency to use the TimerPingSender for maintaining MQTT connections. This implementation is best suited for scenarios where the app is in the foreground.

```kotlin
dependencies {
    implementation "com.gojek.courier:timer-pingsender:x.y.z"
}
```

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

### Define MessageService Interface for Subscribing

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SubscribeUnsubscribe.md

Defines the interface for subscribing and unsubscribing to topics using annotations. Use this to declare your message handling methods.

```kotlin
interface MessageService {
	@Subscribe(topic = "topic/{id}/receive", qos = QoS.ONE)
 	fun subscribe(@Path("id") identifier: String): Observable<Message>
 	
 	@SubscribeMultiple
 	fun subscribeMultiple(@TopicMap topics: Map<String, QoS>): Observable<Message>
 	
	@Unsubscribe(topics = ["topic/{id}/receive"])
 	fun unsubscribe(@Path("id") identifier: String)
}
```

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

### Add Http Authenticator Dependency

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/Authenticator.md

Include the courier-auth-http dependency to use the Http Authenticator. Replace 'x.y.z' with the actual version.

```kotlin
dependencies {
    implementation "com.gojek.courier:courier-auth-http:x.y.z"
}
```

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

### Implement Custom MessageAdapter Factory

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/MessageStreamAdapters.md

Implement the MessageAdapter.Factory interface to create custom message adapters. This factory is responsible for creating instances of your custom MessageAdapter.

```kotlin
class MyCustomMessageAdapterFactory : MessageAdapter.Factory {

    override fun create(type: Type, annotations: Array<Annotation>): MessageAdapter<*> {
        return MyCustomMessageAdapter()
    }
}

private class MyCustomMessageAdapter<T> constructor() : MessageAdapter<T> {

    override fun fromMessage(topic: String, message: Message): T {
        // convert message to custom type
    }

    override fun toMessage(topic: String, data: T): Message {
        // convert custom type to message
    }

    override fun contentType(): String {
        // content-type supported by this adapter.
    }
}
```

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

### Implement Custom StreamAdapter Factory

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/MessageStreamAdapters.md

Implement the StreamAdapter.Factory interface to create custom stream adapters. This factory is used to adapt streams to different stream types.

```kotlin
class MyCustomStreamAdapterFactory : StreamAdapter.Factory {

    override fun create(type: Type): StreamAdapter<Any, Any> {
        return MyCustomStreamAdapter()
    }
}

private class MyCustomStreamAdapter<T> : StreamAdapter<T, Any> {

    override fun adapt(stream: Stream<T>): Any {
        // convert stream to custom stream
    }
}
```

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

### MessageService Interface

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/CourierService.md

Defines the service interface for various messaging actions including Send, Receive, Subscribe, SubscribeMultiple, and Unsubscribe. Each method is annotated to specify the MQTT topic, QoS level, and data handling.

```APIDOC
## MessageService Interface

### Description
Defines the service interface for messaging operations.

### Methods

#### `receive`
- **Purpose**: Receives messages from a specified topic.
- **Annotation**: `@Receive(topic = "topic/{id}/receive")`
- **Parameters**:
  - `identifier` (String) - `@Path("id")` - Identifies the specific topic path.
- **Returns**: `Observable<Message>` - An observable stream of received messages.

#### `send`
- **Purpose**: Sends a message to a specified topic.
- **Annotation**: `@Send(topic = "topic/{id}/send", qos = QoS.TWO)`
- **Parameters**:
  - `identifier` (String) - `@Path("id")` - Identifies the specific topic path.
  - `message` (Message) - `@Data` - The message object to send.

#### `subscribe` (single topic)
- **Purpose**: Subscribes to a single topic for receiving messages.
- **Annotation**: `@Subscribe(topic = "topic/{id}/receive", qos = QoS.ONE)`
- **Parameters**:
  - `identifier` (String) - `@Path("id")` - Identifies the specific topic path.
- **Returns**: `Observable<Message>` - An observable stream of messages from the subscribed topic.

#### `subscribe` (multiple topics)
- **Purpose**: Subscribes to multiple topics simultaneously.
- **Annotation**: `@SubscribeMultiple`
- **Parameters**:
  - `topicMap` (Map<String, QoS>) - `@TopicMap` - A map where keys are topic names and values are their corresponding QoS levels.
- **Returns**: `Observable<Message>` - An observable stream of messages from all subscribed topics.

#### `unsubscribe`
- **Purpose**: Unsubscribes from specified topics.
- **Annotation**: `@Unsubscribe(topics = ["topic/{id}/receive"])`
- **Parameters**:
  - `identifier` (String) - `@Path("id")` - Identifies the specific topic path to unsubscribe from.

```

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

### Add AlarmPingSender Dependency

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/PingSender.md

Include this dependency to utilize the AlarmPingSender for maintaining MQTT connections in the background. Note that on Android 12 and above, scheduling exact alarms requires user permission.

```kotlin
dependencies {
    implementation "com.gojek.courier:alarm-pingsender:x.y.z"
}
```

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

### Define MessageService Interface

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/SendReceiveMessage.md

Defines the interface for sending and receiving messages using the service interface. Use this to declare message sending and receiving methods with specified topics and quality of service.

```kotlin
interface MessageService {
	@Receive(topic = "topic/{id}/receive")
	fun receive(@Path("id") identifier: String): Observable<Message>
	
	@Send(topic = "topic/{id}/send", qos = QoS.TWO)
	fun send(@Path("id") identifier: String, @Data message: Message)
}
```

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

### Add WorkManagerPingSender Dependency

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/PingSender.md

Include this dependency to use the WorkManagerPingSender for maintaining MQTT connections, especially when the app is in the background. Requires WorkManager version 2.7.0 and compileSdkVersion 31 or higher.

```kotlin
dependencies {
    implementation "com.gojek.courier:workmanager-pingsender:x.y.z"
}
```

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

### Add WorkManager-2.6.0 PingSender Dependency

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/PingSender.md

Use this dependency for WorkManager-based ping sending compatible with apps targeting Android versions lower than 31. It helps maintain MQTT connections when the app is in the background.

```kotlin
dependencies {
    implementation "com.gojek.courier:workmanager-2.6.0-pingsender:x.y.z"
}
```

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

### Define Message Service Interface

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/CourierService.md

Declare a service interface for various message actions using annotations like @Receive, @Send, @Subscribe, @SubscribeMultiple, and @Unsubscribe. Path and data parameters are annotated with @Path and @Data respectively.

```kotlin
interface MessageService {
	@Receive(topic = "topic/{id}/receive")
	fun receive(@Path("id") identifier: String): Observable<Message>
	
	@Send(topic = "topic/{id}/send", qos = QoS.TWO)
	fun send(@Path("id") identifier: String, @Data message: Message)
	
	@Subscribe(topic = "topic/{id}/receive", qos = QoS.ONE)
 	fun subscribe(@Path("id") identifier: String): Observable<Message>
	
	@SubscribeMultiple
 	fun subscribe(@TopicMap topicMap: Map<String, QoS>): Observable<Message>
 	
	@Unsubscribe(topics = ["topic/{id}/receive"])
 	fun unsubscribe(@Path("id") identifier: String)
}
```

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

### Disconnect MqttClient

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/ConnectionSetup.md

Gracefully disconnect the MqttClient from the MQTT broker.

```kotlin
mqttClient.disconnect()
```

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

### Subscribe and Unsubscribe Messages

Source: https://github.com/gojek/courier-android/blob/main/README.md

Use the generated message service to subscribe to messages on a specific topic and unsubscribe when no longer needed. The subscribe function returns an Observable that emits incoming messages.

```kotlin
messageService.subscribe("user-id").subscribe {
    print(message)
}
messageService.unsubscribe("user-id")
```

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

### Define Message Service Interface

Source: https://github.com/gojek/courier-android/blob/main/README.md

Declare a service interface using Courier annotations for message operations like receive, send, subscribe, and unsubscribe. Use @Path for topic parameters and @Data for message payloads.

```kotlin
interface MessageService {
	@Receive(topic = "topic/{id}/receive")
	fun receive(@Path("id") identifier: String): Observable<Message>

	@Send(topic = "topic/{id}/send", qos = QoS.TWO)
	fun send(@Path("id") identifier: String, @Data message: Message)

	@Subscribe(topic = "topic/{id}/receive", qos = QoS.ONE)
 	fun subscribe(@Path("id") identifier: String): Observable<Message>

	@Unsubscribe(topics = ["topic/{id}/receive"])
 	fun unsubscribe(@Path("id") identifier: String)
}
```

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

### Disconnect using MqttClient

Source: https://github.com/gojek/courier-android/blob/main/docs/docs/ConnectionSetup.md

Gracefully disconnects the MqttClient from the MQTT broker, terminating the active connection.

```APIDOC
## Disconnect using MqttClient

### Description
Terminates the connection to the MQTT broker.

### Code Example
```kotlin
mqttClient.disconnect()
```
```

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