code: public RouteFilterRuleInner createOrUpdate(String resourceGroupName, String routeFilterName, String ruleName, RouteFilterRuleInner routeFilterRuleParameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, routeFilterName, ruleName, routeFilterRuleParameters).toBlocking().last().body();
      }
docs: Creates or updates a route in the specified route filter.
  
  @param resourceGroupName The name of the resource group.
  @param routeFilterName The name of the route filter.
  @param ruleName The name of the route filter rule.
  @param routeFilterRuleParameters Parameters supplied to the create or update route filter rule operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws CloudException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the RouteFilterRuleInner object if successful.