Last-Wills

A last will is a regular application message, but the client can set up and send it while connecting to the broker. The broker will distribute this last-will only when the client goes offline and the last-will's Delay Interval expires.

Creating a Last-Will¶

A last-will can be created in the connect packget builder callback using ConnectPacketBuilder's WithLastWill and a new LastWillBuilder. The following code creates a last-will that will be published to the "client/last-will" topic 60 seconds after the client gone offline.

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private ConnectPacketBuilder ConnectPacketBuilderCallback(MQTTClient client, ConnectPacketBuilder builder)
{
    return builder.WithLastWill(new LastWillBuilder()
                                    .WithDelayInterval(60)
                                    .WithTopic("client/last-will")
                                    .WithQoS(QoSLevels.ExactlyOnceDelivery)
                                    .WithPayload("This is my last will!"));
}

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