HttpClient中“服务器返回无效或无法识别的响应”的含义

在等待HttpClient .PostAsync响应时,我有时会看到一条错误,指出“服务器返回了无效或无法识别的响应”

 System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.Http.WinHttpException: The server returned an invalid or unrecognized response at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult() at System.Net.Http.WinHttpHandler.d__105.MoveNext() --- End of inner exception stack trace --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult() at System.Net.Http.HttpClient.d__58.MoveNext() 

这是一个非常神秘的错误; 我想我可以设想一个“无效”的响应可能是什么(即语法无效的HTTP响应,比如直接跳转到没有状态行的头部的响应),但实际上是对HTTP的“无法识别的”响应请求? 这条消息似乎是无稽之谈。

在引擎盖下,什么情况下实际上可以触发这个错误?