public function execute($returnTransfer = TRUE) {
        //Need transfer return
        if($returnTransfer === TRUE) {
            $this->setOption(CURLOPT_RETURNTRANSFER, 1);
        }

        $result = curl_exec($this->handler);

        //Error handling
        if(curl_errno($this->handler)) {
            $format = [curl_errno($this->handler), curl_error($this->handler)];
            $this->close();
            throw RuntimeException::createByFormat('Error executing request, error code: %s, Message: %s', $format);
        }

        return $result;
    }