code: func TransactionSetRequestURL(id int64, url string) (int, error) {
  	curl := C.CString(url)
  	defer C.free(unsafe.Pointer(curl))
  
  	return errNo(C.newrelic_transaction_set_request_url(C.long(id), curl))
  }
docs: /*
   * Set the request url of a transaction. The query part of the url is
   * automatically stripped from the url.
   *
   * @param transaction_id  id of transaction
   * @param request_url  request url for a web transaction
   * @return  0 on success, else negative warning code or error code
   */