Connect to a broker with will message

Private Sub Connect_WithWillMsg()
On Error GoTo errExit
    Dim connOption As MQTTConnectOption
    Dim retCode As MqttConnectionCode
    
    Set mFactory = Application.CreateMQTT
    Set mClient = mFactory.CreateClient
    Set connOption = mFactory.CreateConnectOption()
    
    connOption.ClientID = "Client01"
    connOption.Version = MqttVersion500
    connOption.Protocol = MqttProtocolTcp
    connOption.WithTcpServer "broker.com", 1883
    
    Dim will As MQTTWillMessage
    Set will = connOption.WillMessage
    
    will.PayloadFormat = MqttPayloadCharacter
    will.contenttype = "String"
    will.payload = "This is will message."
    will.Topic = "SE"
    Dim data() As Byte
    data = StrConv("This is the correlation.", vbFromUnicode)
    will.correlation = data
    will.ResponseTopic = "This is the response topic."
    will.AddUserProperty "Head1", "Node1"
    will.QoS = MqttQoS2
    will.retain = True
    
    retCode = mClient.Connect(connOption)
    Exit Sub
    
errExit:
    MsgBox err.Description
End Sub