I have a custom content approval workflow that worked in Umbraco 7 by subscribing to the content_publishing event and changing a field on the node using the ContentService API to update approval state.

In Umbraco 8 using the .Save method

    public void UpdateWaitingApprovalStatus(IContent contentToUpdate, string waitingApprovalPropertyAlias, string waitingApprovalValueToSet)
    {
        contentToUpdate.SetValue(waitingApprovalPropertyAlias, waitingApprovalValueToSet);
        _contentService.Save(contentToUpdate);
    }

I get the following error Cannot save (un)publishing content with name: test - and state: Publishing, use the dedicated SavePublished method.

But I can't seem to find that method anywhere, is there another way to save while PublishedState is Publishing?

I can get around it by subscribing to the published event and using SaveAndPublish but that leaves two publish events in logs.