code: public Observable<NetworkInterfaceInner> getVirtualMachineScaleSetNetworkInterfaceAsync(String resourceGroupName, String virtualMachineScaleSetName, String virtualmachineIndex, String networkInterfaceName, String expand) {
          return getVirtualMachineScaleSetNetworkInterfaceWithServiceResponseAsync(resourceGroupName, virtualMachineScaleSetName, virtualmachineIndex, networkInterfaceName, expand).map(new Func1<ServiceResponse<NetworkInterfaceInner>, NetworkInterfaceInner>() {
              @Override
              public NetworkInterfaceInner call(ServiceResponse<NetworkInterfaceInner> response) {
                  return response.body();
              }
          });
      }
docs: Get the specified network interface in a virtual machine scale set.
  
  @param resourceGroupName The name of the resource group.
  @param virtualMachineScaleSetName The name of the virtual machine scale set.
  @param virtualmachineIndex The virtual machine index.
  @param networkInterfaceName The name of the network interface.
  @param expand Expands referenced resources.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the NetworkInterfaceInner object