BeginAcceptTcpClient и AcceptTcpClient: в чем разница

// Thread signal.
        public static ManualResetEvent tcpClientConnected =
            new ManualResetEvent(false);
 
        // Accept one client connection asynchronously.
        public static void DoBeginAcceptTcpClient(TcpListener
            listener)
        {
            // Set the event to nonsignaled state.
            tcpClientConnected.Reset();
 
            // Start to listen for connections from a client.
            Console.WriteLine("Waiting for a connection...");
 
            // Accept the connection. 
            // BeginAcceptSocket() creates the accepted socket.
            listener.BeginAcceptTcpClient(
                new AsyncCallback(DoAcceptTcpClientCallback),
                listener);
 
            // Wait until a connection is made and processed before 
            // continuing.
            tcpClientConnected.WaitOne();
        }
 
 
        // Process the client connection.
        public static void DoAcceptTcpClientCallback(IAsyncResult ar)
        {
            // Get the listener that handles the client request.
            TcpListener listener = (TcpListener)ar.AsyncState;
 
            // End the operation and display the received data on 
            // the console.
            TcpClient client = listener.EndAcceptTcpClient(ar);
 
            // Process the connection here. (Add the client to a
            // server table, read data, etc.)
            Console.WriteLine("Client connected completed");
                        
            // Signal the calling thread to continue.
            tcpClientConnected.Set();
 
        }