Modulo com erro, ajuda aqui

Question

Estou fazendo um servidor para interagir com mult-clientes, mas ele da alguns erros

-Error 9 Type 'NetworkStream' is not defined.

-Error 6 Type 'NetworkStream' is not defined.

-Error 5 Type 'TcpClient' is not defined

Fonte :

Imports System.Net
Imports System.Text
Module Module1
    Dim listaClientes As New Hashtable

    Sub Main()
        Dim enderecoLocal As IPAddress = IPAddress.Parse("127.0.0.1")
        Dim serverSocket As New TcpListener(enderecoLocal, 8888)
        Dim clientSocket As TcpClient = Nothing
        Dim contador As Integer
        serverSocket.Start()
        Mensagem("Servidor Chat Iniciado ....")
        contador = 0
        While (True)
            contador += 1
            clientSocket = serverSocket.AcceptTcpClient()
            Dim bytesFrom(10024) As Byte
            Dim dadosDoCliente As String
            Dim networkStream As NetworkStream = clientSocket.GetStream()
            networkStream.Read(bytesFrom, 0, CInt(clientSocket.ReceiveBufferSize))
            dadosDoCliente = Encoding.ASCII.GetString(bytesFrom)
            dadosDoCliente = dadosDoCliente.Substring(0, dadosDoCliente.IndexOf("$"))
            listaClientes(dadosDoCliente) = clientSocket
            broadcast(dadosDoCliente + " Entrou ", dadosDoCliente, False)
            Mensagem(dadosDoCliente + " Entrou na Sala ")
            Dim cliente As New tratarCliente
            cliente.iniciaCliente(clientSocket, dadosDoCliente, listaClientes)
        End While
        clientSocket.Close()
        serverSocket.Stop()
        Mensagem("sair")
        Console.ReadLine()
    End Sub
    Sub Mensagem(ByVal texto As String)
        texto.Trim()
        Console.WriteLine(" >> " + texto)
    End Sub
    Private Sub broadcast(ByVal Mensagem As String, ByVal nomeUsuario As String, ByVal flag As Boolean)
        Dim Item As DictionaryEntry
        For Each Item In listaClientes
            Dim broadcastSocket As TcpClient
            broadcastSocket = CType(Item.Value, TcpClient)
            Try
                Dim broadcastStream As NetworkStream = broadcastSocket.GetStream()
                Dim broadcastBytes As [Byte]()
                If flag = True Then
                    broadcastBytes = Encoding.ASCII.GetBytes(nomeUsuario + " diz : " + Mensagem)
                Else
                    broadcastBytes = Encoding.ASCII.GetBytes(Mensagem)
                End If
                broadcastStream.Write(broadcastBytes, 0, broadcastBytes.Length)
                broadcastStream.Flush()
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try
        Next
    End Sub
    Public Class tratarCliente
        Dim clientSocket As TcpClient
        Dim clNo As String
        Dim listaClientes As Hashtable
        Public Sub iniciaCliente(ByVal inClientSocket As TcpClient, ByVal clineNo As String, ByVal cList As Hashtable)
            Me.clientSocket = inClientSocket
            Me.clNo = clineNo
            Me.listaClientes = cList
            Dim ctThread As Threading.Thread = New Threading.Thread(AddressOf doChat)
            ctThread.Start()
        End Sub
        Private Sub doChat()
            Dim contadorRequisicao As Integer
            Dim bytesFrom(10024) As Byte
            Dim dadosDoCliente As String
            Dim rContador As String
            contadorRequisicao = 0
            While (True)
                Try
                    contadorRequisicao = contadorRequisicao + 1
                    Dim networkStream As NetworkStream = clientSocket.GetStream()
                    networkStream.Read(bytesFrom, 0, CInt(clientSocket.ReceiveBufferSize))
                    dadosDoCliente = System.Text.Encoding.ASCII.GetString(bytesFrom)
                    dadosDoCliente = dadosDoCliente.Substring(0, dadosDoCliente.IndexOf("$"))
                    Mensagem("Cliente - " + clNo + " : " + dadosDoCliente)
                    rContador = Convert.ToString(contadorRequisicao)
                    broadcast(dadosDoCliente, clNo, True)
                Catch ex As Exception
                    MsgBox(ex.ToString)
                End Try
            End While
        End Sub
    End Class
End Module

Answer 1

Imports System.Net.Sockets