Maknz\Slack\Client::createMessage PHP Method

    public function createMessage()
    {
        $message = new Message($this);
        $message->setChannel($this->getDefaultChannel());
        $message->setUsername($this->getDefaultUsername());
        $message->setIcon($this->getDefaultIcon());
        $message->setAllowMarkdown($this->getAllowMarkdown());
        $message->setMarkdownInAttachments($this->getMarkdownInAttachments());
        return $message;
    }

 /**
  * Sends the log message to slack.
  */
 public function export()
 {
     $error = ArrayHelper::getValue($this->messages[0], 0, 'Unknown Error');
     $message = $this->client->createMessage();
     $text = is_object($error) ? $error->__toString() : $error;
     $message->attach(['title' => ArrayHelper::getValue($this->messages[0], 2, 'Site Error'), 'text' => $text, 'fallback' => $text, 'color' => $this->color, 'fields' => $this->getContextAttachment()]);
     $message->send();
 }