The example below shows how to check if a mail is attempted.
Sample: Fetching mail header data
<?php
$mail = new Mailer;
$mail->server('mail.server'); // load server config file
$mail->setup([
'client' => ['name' => 'Foo']
]);
$mail->authorize(true);
$mail->sendmail();
if($mail->attempted()){
// ...do this
} else {
// ...no attempt was made
}