/// <summary>
 /// 列出 config 应用的机器列表。
 /// </summary>
 /// <param name="client">client实例。</param>
 /// <param name="configName">日志配置名称。</param>
 /// <param name="project">项目名,此参数将覆盖 client 中默认设置。</param>
 /// <returns>异步响应结果。</returns>
 /// <seealso cref="ILogServiceClient.GetAppliedMachineGroupsAsync"/>
 public static Task <IResponse <GetAppliedMachineGroupsResult> > GetAppliedMachineGroupsAsync(this ILogServiceClient client,
                                                                                              String configName,
                                                                                              String project = null)
 => client.GetAppliedMachineGroupsAsync(new GetAppliedMachineGroupsRequest(configName)
 {
     ProjectName = project
 });