Sending multiple emails in parallel using SmtpClient.SendMailAsync with async and Task.WhenAll

sendemailsasync.cs

var sendEmailTasks = recipientList.Select(async recipient =>
{
    var message = new MailMessage { To = { recipient }, ... };

    // instantiate a new client for each mail because of this:
    // http://www.codefrenzy.net/2012/01/30/how-asynchronous-is-smtpclient-sendasync/
    using (var smtpClient = new SmtpClient())
    {
        await smtpClient.SendMailAsync(message);
    }
});
await Task.WhenAll(sendEmailTasks);