public function attachment(Closure $callback)
    {
        $this->attachments[] = $attachment = new SlackAttachment;

        $callback($attachment);

        return $this;
    }
public function attachment(Closure $callback)
    {
        $this->attachments[] = $attachment = new SlackAttachment;

        $callback($attachment);

        return $this;
    }
public function attachment ( Closure $ callback ) { $ this -> attachments [ ] = $ attachment = new SlackAttachment ; $ callback ( $ attachment ) ; return $ this ; }
Define an attachment for the message.

@param  \Closure  $callback
@return $this
Define an attachment for the message .