public override void Send (FormatOptions options, MimeMessage message, CancellationToken cancellationToken = default (CancellationToken), ITransferProgress progress = null)
{
if (options == null)
throw new ArgumentNullException (nameof (options));
if (message == null)
throw new ArgumentNullException (nameof (message));
var recipients = GetMessageRecipients (message);
var sender = GetMessageSender (message);
if (sender == null)
throw new InvalidOperationException ("No sender has been specified.");
if (recipients.Count == 0)
throw new InvalidOperationException ("No recipients have been specified.");
Send (options, message, sender, recipients, cancellationToken, progress);
}