def start_osupgrade(resource_group_name, vm_scale_set_name, custom_headers:nil)
      response = start_osupgrade_async(resource_group_name, vm_scale_set_name, custom_headers:custom_headers).value!
      response.body unless response.nil?
    end
def start_osupgrade(resource_group_name, vm_scale_set_name, custom_headers:nil)
      response = start_osupgrade_async(resource_group_name, vm_scale_set_name, custom_headers:custom_headers).value!
      response.body unless response.nil?
    end
Starts a rolling upgrade to move all virtual machine scale set instances to
 the latest available Platform Image OS version. Instances which are already
 running the latest available OS version are not affected.

 @param resource_group_name [String] The name of the resource group.
 @param vm_scale_set_name [String] The name of the VM scale set.
 @param custom_headers [Hash{String => String}] A hash of custom headers that
 will be added to the HTTP request.

 @return [OperationStatusResponse] operation results.