src/Broadcast/Broadcast.php
public function previewCard($message, $to, $by = self::PREVIEW_BY_OPENID)
    {
        return $this->preview(self::MSG_TYPE_CARD, $message, $to, $by);
    }
public function previewCard($message, $to, $by = self::PREVIEW_BY_OPENID)
    {
        return $this->preview(self::MSG_TYPE_CARD, $message, $to, $by);
    }
Preview a card message.

@param mixed  $message message
@param string $to
@param string $by

@return mixed