Tcpclient doesn't wait for data to arrive before completing

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VB

TcpClient

Ok, So I'm not an expert or anywhere close. I write in VB as a hobby and have written plenty of small apps and the majority of them are for old serial device connections.
Now those devices are connecting via TCP. Easy, So I thought...
My server is a embedded SBC and very structured in its communication protocol. All data terminates with a fixed character ETX (ChrW(3)). So I should be able to get incoming response stream and save it to a string until the ETX arrives.
This also is a single click button, connect-send-receive sub.
Having a separate connect/disconnect button would be helpful as sometime multiple commands would be sent and connecting/disconnecting repeatedly seems ridiculous.
Any help would be great.
Kevin

Shared Sub Connect(server As [String], port as [Int32], message As [String])
   Try
      Dim client As New TcpClient(server, port)
      Dim data As [Byte]() = System.Text.Encoding.ASCII.GetBytes(message)
      Dim stream As NetworkStream = client.GetStream()

      stream.Write(data, 0, data.Length)

      RTB1_update("Sent: {0}", message)

      data = New [Byte](256) {}

      Dim responseData As [String] = [String].Empty

      Threading.thread.sleep(2000)

      Dim bytes As Int32 = stream.Read(data, 0, data.Length)
      responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes)
      RTB1_update("Received: {0}", responseData)

      stream.Close()
      client.Close()
   Catch e As ArgumentNullException
      RTB1_update("ArgumentNullException: {0}", e)
   Catch e As SocketException
      RTB1_update("SocketException: {0}", e)
   End Try

End Sub

What I have tried:

No matter what I do it fails to do this and waiting for a timeout approx 90 seconds is a joke. The code below is straight off of MSDN and completes long before the data even arrives. Adding a thread.sleep for a second or two helps, but some data is long and gets clipped, some is very short and the long unneeded wait is silly,