public void testGreetingClient()
{
//下面是这个过程的输出
//2020.07.17 10:11:55:536 testGreetingClient enter in thread 13 and no task
//2020.07.17 10:11:55:538 callGreetingClientAsync enter in thread 13 and no task
//2020.07.17 10:11:55:539 running GreetingAsync in thread 11 and task 1
//2020.07.17 10:11:55:539 running Greeting in thread 11 and task 1
//2020.07.17 10:11:55:539 testGreetingClient got Task<String> greetingResult, and next to get greetingResult.Result in thread 13 and no task
//这里有个500毫秒的gap（当时Greeting方法正在blocking wait）
//2020.07.17 10:11:56:050 callGreetingClientAsync done in thread 11 and no task
//2020.07.17 10:11:56:050 testGreetingClient done - got greetingResult.Result:Hello, HanMeiMei in thread 13 and no task
ThirdPartyAsyncSimulator greetingClient = new ThirdPartyAsyncSimulator();
//线程A - 调用者当前线程
ThreadEval_Util.TraceThreadAndTask($"{nameof(testGreetingClient)} enter");
Task <String> greetingResult = callGreetingClientAsync();
ThreadEval_Util.TraceThreadAndTask($"{nameof(testGreetingClient)} got Task<String> greetingResult, and next to get greetingResult.Result");
//线程A - 前面都很快，而执行这个获取task结果卡住了，因为结果还没有出来
String greetingResultStr = greetingResult.Result;
//线程A - 这里线程没变
ThreadEval_Util.TraceThreadAndTask($"{nameof(testGreetingClient)} done - got greetingResult.Result:{greetingResultStr}");
}
public async Task <String> callGreetingClientAsync()
{
ThirdPartyAsyncSimulator greetingClient = new ThirdPartyAsyncSimulator();
//线程A - 就是调用者所在的线程
ThreadEval_Util.TraceThreadAndTask($"{nameof(callGreetingClientAsync)} enter");
Task <String> greetingResult = greetingClient.GreetingAsync("HanMeiMei");
//一旦开始await，这个方法就返回了。调用方法立马得到了Task<String>的结果
//String greetingResultStr = await greetingResult;
//这里使用await greetingResult与 await greetingResult.ConfigureAwait(false)是一样的
//note：但是如果是UI程序，或者asp.net则不一样
//使用ConfigureAwait(false)的目的是让醒来后的线程可以是随意一个线程池中的线程
//见本类开头更多总结
String greetingResultStr = await greetingResult.ConfigureAwait(false);
//线程B - await之后，task执行之后，处理执行结果是其他线程（不再保证是进入是的线程A）
ThreadEval_Util.TraceThreadAndTask($"{nameof(callGreetingClientAsync)} done");
return(greetingResultStr);
}
