code: public ExpressRouteConnectionInner createOrUpdate(String resourceGroupName, String expressRouteGatewayName, String connectionName, ExpressRouteConnectionInner putExpressRouteConnectionParameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, expressRouteGatewayName, connectionName, putExpressRouteConnectionParameters).toBlocking().last().body();
      }
docs: Creates a connection between an ExpressRoute gateway and an ExpressRoute circuit.
  
  @param resourceGroupName The name of the resource group.
  @param expressRouteGatewayName The name of the ExpressRoute gateway.
  @param connectionName The name of the connection subresource.
  @param putExpressRouteConnectionParameters Parameters required in an ExpressRouteConnection PUT 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 ExpressRouteConnectionInner object if successful.