System.Net.Mail.SmtpConnection.ConnectAndHandshakeAsyncResult.SendStartTls C# (CSharp) Method

            private bool SendStartTls()
            {
                IAsyncResult result = StartTlsCommand.BeginSend(_connection, SendStartTlsCallback, this);
                if (result.CompletedSynchronously)
                {
                    StartTlsCommand.EndSend(result);
                    TlsStreamAuthenticate();
                    return true;
                }
                return false;
            }

 private static void SendEHelloCallback(IAsyncResult result)
 {
     if (!result.CompletedSynchronously)
     {
         SmtpConnection.ConnectAndHandshakeAsyncResult asyncState = (SmtpConnection.ConnectAndHandshakeAsyncResult)result.AsyncState;
         try
         {
             try
             {
                 asyncState.connection.extensions = EHelloCommand.EndSend(result);
                 asyncState.connection.ParseExtensions(asyncState.connection.extensions);
                 if (asyncState.connection.pooledStream.NetworkStream is TlsStream)
                 {
                     asyncState.Authenticate();
                     return;
                 }
             }
             catch (SmtpException exception)
             {
                 if ((exception.StatusCode != SmtpStatusCode.CommandUnrecognized) && (exception.StatusCode != SmtpStatusCode.CommandNotImplemented))
                 {
                     throw exception;
                 }
                 if (!asyncState.SendHello())
                 {
                     return;
                 }
             }
             if (asyncState.connection.EnableSsl)
             {
                 if (!asyncState.connection.serverSupportsStartTls && !(asyncState.connection.pooledStream.NetworkStream is TlsStream))
                 {
                     throw new SmtpException(SR.GetString("MailServerDoesNotSupportStartTls"));
                 }
                 asyncState.SendStartTls();
             }
             else
             {
                 asyncState.Authenticate();
             }
         }
         catch (Exception exception2)
         {
             asyncState.InvokeCallback(exception2);
         }
     }
 }