code: public Observable<ExpressRouteCircuitPeeringInner> createOrUpdateAsync(String resourceGroupName, String circuitName, String peeringName, ExpressRouteCircuitPeeringInner peeringParameters) {
          return createOrUpdateWithServiceResponseAsync(resourceGroupName, circuitName, peeringName, peeringParameters).map(new Func1<ServiceResponse<ExpressRouteCircuitPeeringInner>, ExpressRouteCircuitPeeringInner>() {
              @Override
              public ExpressRouteCircuitPeeringInner call(ServiceResponse<ExpressRouteCircuitPeeringInner> response) {
                  return response.body();
              }
          });
      }
docs: Creates or updates a peering in the specified express route circuits.
  
  @param resourceGroupName The name of the resource group.
  @param circuitName The name of the express route circuit.
  @param peeringName The name of the peering.
  @param peeringParameters Parameters supplied to the create or update express route circuit peering operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable for the request