Update the message time before sending, fixes #424

src/Monolog/Handler/MandrillHandler.php

@@ -50,6 +50,7 @@ class MandrillHandler extends MailHandler
     {
         $message = clone $this->message;
         $message->setBody($content);
+        $message->setDate(time());
 
         $ch = curl_init();
 

src/Monolog/Handler/SwiftMailerHandler.php

@@ -49,6 +49,7 @@ class SwiftMailerHandler extends MailHandler
     {
         $message = clone $this->message;
         $message->setBody($content);
+        $message->setDate(time());
 
         $this->mailer->send($message);
     }