code: public Observable<VirtualMachineScaleSetVMInner> beginUpdateAsync(String resourceGroupName, String vmScaleSetName, String instanceId, VirtualMachineScaleSetVMInner parameters) {
          return beginUpdateWithServiceResponseAsync(resourceGroupName, vmScaleSetName, instanceId, parameters).map(new Func1<ServiceResponse<VirtualMachineScaleSetVMInner>, VirtualMachineScaleSetVMInner>() {
              @Override
              public VirtualMachineScaleSetVMInner call(ServiceResponse<VirtualMachineScaleSetVMInner> response) {
                  return response.body();
              }
          });
      }
docs: Updates a virtual machine of a VM scale set.
  
  @param resourceGroupName The name of the resource group.
  @param vmScaleSetName The name of the VM scale set where the extension should be create or updated.
  @param instanceId The instance ID of the virtual machine.
  @param parameters Parameters supplied to the Update Virtual Machine Scale Sets VM operation.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the VirtualMachineScaleSetVMInner object