public:
    static void RetryIfBusy(String* server)
    {
       MailAddress* from = new MailAddress(S"ben@contoso.com");
       MailAddress* to = new MailAddress(S"jane@contoso.com");
       MailMessage* message = new MailMessage(from, to);
       // message.Subject = "Using the SmtpClient class.";
       message->Subject = S"Using the SmtpClient class.";
       message->Body = S"Using this feature, you can send an e-mail message from an application very easily.";
       // Add a carbon copy recipient.
       MailAddress* copy= new MailAddress(S"Notifications@contoso.com");
       message->CC->Add(copy);
       SmtpClient* client = new SmtpClient(server);
        // Include credentials if the server requires them.
       client->Credentials = dynamic_cast<ICredentialsByHost*> (CredentialCache::DefaultNetworkCredentials);
       Console::WriteLine(S"Sending an e-mail message to {0} using the SMTP host {1}.", 
            to->Address, client->Host);
       try 
       {
            client->Send(message);
       }
       catch (SmtpFailedRecipientsException* ex)
       {
           for (int i = 0; i<ex->Exceptions->Length; i++)
           {
                SmtpStatusCode status = ex->Exceptions[i]->StatusCode;
               if (status == SmtpStatusCode::MailboxBusy ||
                   status == SmtpStatusCode::MailboxUnavailable)
               {
                    Console::WriteLine(S"Delivery failed - retrying in 5 seconds.");
                    System::Threading::Thread::Sleep(5000);
                    client->Send(message);
                }
                else
                {
                    Console::WriteLine(S"Failed to deliver message to {0}", ex->FailedRecipients[i]);
                }
            }
       }
       __finally
       {
            client->Dispose();
       }
}