Zauważyłem to, gdy używamSystem.Net.HttpClient z krótkim czasem oczekiwania może czasami przerwać proces, nawet jeśli jest zawinięty w blok try-catch. Oto krótki program do odtworzenia tego.

public static void Main(string[] args)
{
    var tasks = new List<Task>();
    for (int i = 0; i < 1000; i++)
    {
        tasks.Add(MakeHttpClientRequest());
    }
    Task.WaitAll(tasks.ToArray());

}

private async static Task MakeHttpClientRequest()
{            
    var httpClient = new HttpClient { Timeout = TimeSpan.FromMilliseconds(1) };
    var request = "whatever";
    try
    {
        HttpResponseMessage result =
            await httpClient.PostAsync("http://www.flickr.com/services/rest/?method=flickr.test.echo&format=json&api_key=766c0ac7802d55314fa980727f747710",
                                 new StringContent(request));             
        await result.Content.ReadAsStringAsync();                
    }
    catch (Exception x)
    {
        Console.WriteLine("Error occurred but it is swallowed: " + x);
    }
}

Uruchomienie tego spowoduje awarię procesu z następującym wyjątkiem:

Unhandled Exception: System.AggregateException: One or more errors occurred. ---> System.Net.WebException: The request was canceled
   at System.Net.ServicePointManager.FindServicePoint(Uri address, IWebProxy proxy, ProxyChain& chain, HttpAbortDelegate& abortDelegate, Int32& abortState)
   at System.Net.HttpWebRequest.FindServicePoint(Boolean forceFind)
   at System.Net.HttpWebRequest.get_ServicePoint()
   at System.Net.AuthenticationState.PrepareState(HttpWebRequest httpWebRequest)
   at System.Net.AuthenticationState.ClearSession(HttpWebRequest httpWebRequest)
   at System.Net.HttpWebRequest.ClearAuthenticatedConnectionResources()
   at System.Net.HttpWebRequest.Abort(Exception exception, Int32 abortState)
   at System.Net.HttpWebRequest.Abort()
   at System.Net.Http.HttpClientHandler.OnCancel(Object state)
   at System.Threading.CancellationCallbackInfo.ExecutionContextCallback(Object obj)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.CancellationCallbackInfo.ExecuteCallback()
   at System.Threading.CancellationTokenSource.CancellationCallbackCoreWork(CancellationCallbackCoreWorkArguments args)
   at System.Threading.CancellationTokenSource.ExecuteCallbackHandlers(Boolean throwOnFirstException)
   --- End of inner exception stack trace ---
   at System.Threading.CancellationTokenSource.ExecuteCallbackHandlers(Boolean throwOnFirstException)
   at System.Threading.CancellationTokenSource.NotifyCancellation(Boolean throwOnFirstException)
   at System.Threading.CancellationTokenSource.TimerCallbackLogic(Object obj)
   at System.Threading.TimerQueueTimer.CallCallbackInContext(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.TimerQueueTimer.CallCallback()
   at System.Threading.TimerQueueTimer.Fire()
   at System.Threading.TimerQueue.FireNextTimers()
   at System.Threading.TimerQueue.AppDomainTimerCallback()

Kopiąc trochę, wydaje się, że kiedyHttpClient przerywa żądanie przed odpowiednimServicePoint jest tworzone,HttpWebRequest próbuje utworzyćServicePoint, przezServicePointManager.FindServicePoint, który zgłasza RequestCanceled. Ponieważ ten wyjątek jest generowany w wątku, który próbuje anulować żądanie, nie zostaje on przechwycony, a proces umiera.

Czy czegoś mi brakuje? Czy natknąłeś się na ten problem?