public TestStatelessService(StatelessServiceContext context)
            : base(context)
{
  var configPkg = context.CodePackageActivationContext.GetConfigurationPackageObject("Config");
  var customConfigFilePath = configPkg.Path + @"\testconfig.xml";  

  var services = ConfigureServices();
  services.GetService<ILoggerFactory>()
          .AddLog4Net(customConfigFilePath);
}

internal static IServiceProvider ConfigureServices()
{            
  return new ServiceCollection()
      .AddLogging()
      .AddSingleton<ILoggerFactory, LoggerFactory>()
      .BuildServiceProvider();
}