Message Event (Received messages)

Private Sub mClient_ApplicationMessage(ByVal msgEvent As MQTTMessageEvent)
On Error GoTo errExit
    Dim payloadText As String
    Dim i As Integer

    payloadText = msgEvent.Message.PayloadAsText
    MsgBox msgEvent.Message.Topic + ": " + payloadText
    
    'Get more advanced MQTT properties from payload
    Dim subIDsText As String
    Dim subIDs() As Long
    If VarType(msgEvent.Message.SubscriptionIdentifiers) <> Empty Then
        subIDs = msgEvent.Message.SubscriptionIdentifiers
        
        For i = LBound(subIDs) To UBound(subIDs)
            subIDsText = subIDsText & CStr(subIDs(i))
        Next i
    End If
    
    Dim corrDataText As String
    If VarType(msgEvent.Message.Correlation) <> Empty Then
        corrDataText = StrConv(msgEvent.Message.Correlation, vbUnicode)
    End If
    
    Dim userPropsText As String
    Dim userProps() As MQTTUserProperty
    If VarType(msgEvent.Message.UserProperties) <> Empty Then
        userProps = msgEvent.Message.UserProperties
        
        For i = LBound(userProps) To UBound(userProps)
            userPropsText = userPropsText + userProps(i).Name + ":" + userProps(i).Value
        Next
    End If
    
    MsgBox CStr(msgEvent.Message.QoS) + CStr(msgEvent.Message.Retain) + CStr(msgEvent.Message.MessageExpiryInterval) + CStr(msgEvent.Message.PayloadFormat) + msgEvent.Message.ContentType + subIDsText + msgEvent.Message.ResponseTopic + corrDataText + userPropsText
    
    Exit Sub
    
errExit:
    MsgBox err.Description
End Sub