[ObsoleteAttribute("This method is obsolete in .NET 4.5+. Use StartTlsAsync instead.")]
public IAsyncResult BeginStartTls(
	AsyncCallback callback,
	Object state
)

<ObsoleteAttribute("This method is obsolete in .NET 4.5+. Use StartTlsAsync instead.")>
Public Function BeginStartTls ( 
	callback As AsyncCallback,
	state As Object
) As IAsyncResult

// To use the code below, import MailBee namespaces at the top of your code.
using MailBee;
using MailBee.SmtpMail;

// Put the code below inside your class.

// TlsStarted event handler.
private void OnTlsStarted(object sender, TlsStartedEventArgs e)
{
    MessageBox.Show("TLS/SSL negotiation complete. Secure connection is ready.");
}

// The actual code.
private void Form1_Load(object sender, System.EventArgs e)
{
    Smtp mailer = new Smtp();

    // Let MailBee process events.
    mailer.RaiseEventsViaMessageLoop = false;

    mailer.SmtpServers.Add("smtp.domain.com");

    mailer.TlsStarted += new TlsStartedEventHandler(OnTlsStarted);

    mailer.Connect();
    mailer.Hello();

    // Initiate an asynchronous TLS/SSL negotiation.
    mailer.BeginStartTls(null, null);

    // Simulate some lengthy work here...
    for (int i = 0; i < 100; i++)
    {
        // Make a portion of the work.
        System.Threading.Thread.Sleep(10);

        // Process events which were raised during execution of the work above.
        mailer.Wait(0);
    }

    // If the connection was not established during execution of the lengthy 
    // work, wait until it's established.
    mailer.Wait();

    // End the connection request.
    mailer.EndStartTls();

    // The connection is now under TLS/SSL layer!

    mailer.Hello();

    // Disconnect from the server.
    mailer.Disconnect();
}

' To use the code below, import MailBee namespaces at the top of your code.
Imports MailBee
Imports MailBee.SmtpMail

' Put the code below inside your class.

' TlsStarted event handler.
Private Sub OnTlsStarted(ByVal sender As Object, ByVal e As TlsStartedEventArgs)
    MsgBox("TLS/SSL negotiation complete. Secure connection is ready.")
End Sub

' The actual code.
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs)
    Dim mailer As New Smtp

    ' Let MailBee process events.
    mailer.RaiseEventsViaMessageLoop = False

    mailer.SmtpServers.Add("smtp.domain.com")

    AddHandler mailer.TlsStarted, AddressOf OnTlsStarted

    mailer.Connect()
    mailer.Hello()

    ' Initiate an asynchronous TLS/SSL negotiation.
    mailer.BeginStartTls(Nothing, Nothing)

    ' Simulate some lengthy work here...
    Dim i As Integer
    For i = 1 To 100
        ' Make a portion of the work.
        System.Threading.Thread.Sleep(10)

        ' Process events which were raised during execution of the work above.
        mailer.Wait(0)
    Next

    ' If the connection was not established during execution of the lengthy 
    ' work, wait until it's established.
    mailer.Wait()

    ' End the connection request.
    mailer.EndStartTls()

    ' The connection is now under TLS/SSL layer!

    mailer.Hello()

    ' Disconnect from the server.
    mailer.Disconnect()
End Sub