code: public function flushDomainCacheRule($domain, $ruleId)
      {
          return json_decode(self::getClient()->flushDomainCacheRule($this->sn, $domain, $ruleId));
      }
docs: Flush cache rule $ruleId of domain $domain
  
  @param string $domain
  @param integer $ruleId
  @return object Task