Как сделать так, чтобы при закрытии клиента закрывался и сервер?

Dim objClient As Client
    Dim d As DictionaryEntry
 
    For Each d In mcolClients
      objClient = d.Value
      objClient.Send("DIE!")
    Next

 Private Sub DoRead(ByVal ar As IAsyncResult)
    Dim intCount As Integer
 
    Try
      intCount = mobjClient.GetStream.EndRead(ar)
      If intCount < 1 Then
        MarkAsDisconnected()
        Exit Sub
            End If
            Dim st As String = System.Text.Encoding.Default.GetString(marData)
            If InStr(st, "DIE!") <> 0 Then End
            BuildString(marData, 0, intCount)
 
            mobjClient.GetStream.BeginRead(marData, 0, 1024, AddressOf DoRead, Nothing)
        Catch e As Exception
            MarkAsDisconnected()
        End Try
  End Sub

Private Sub OnLineReceived(ByVal sender As Client, ByVal Data As String)
 
If Data = "SHOW MY IP" Then UpdateStatus("IP:" & sender.IP)
UpdateStatus("Line:" & Data)

    Public ReadOnly Property IP() As String
        Get
            Return mobjClient.Client.RemoteEndPoint.ToString
        End Get
    End Property