private static IEnumerable <Async> SimpleYield(Async async)
{
yield return(async);
}
/// <summary>
/// 执行异步操作，不等待结果返回
/// </summary>
/// <param name="async">需要执行的异步操作</param>
public static void Execute(this Async async)
{
Execute(SimpleYield(async));
}
