public async Task<int> SaveChangesAsync(string userName, string impersonatorId)
    {
        try
        {
            AddMetadataToEntity(userName, impersonatorId);
            var audit = new Audit();

            audit.CreatedBy = impersonatorId != null ? impersonatorId : userName;

            audit.PreSaveChanges(this);
            int rowAffected = await base.SaveChangesAsync().ConfigureAwait(false);
            audit.PostSaveChanges();

            if (audit.Configuration.AutoSavePreAction != null)
            {
                audit.Configuration.AutoSavePreAction(this, audit);
                await base.SaveChangesAsync().ConfigureAwait(false);
            }

            return rowAffected;
        }
        catch (DbUpdateConcurrencyException ex)
        {
            foreach (EntityEntry entry in ex.Entries)
            {
                System.Diagnostics.Debug.WriteLine(entry.GetType().Name);
                foreach (Microsoft.EntityFrameworkCore.Metadata.IProperty prop in entry.CurrentValues.Properties)
                {
                    System.Diagnostics.Debug.WriteLine("t" + prop.Name);
                    System.Diagnostics.Debug.WriteLine("t" + entry.CurrentValues[prop]);
                }
            }
            throw ex;
        }
    }