使用带超时的事件时出现NullReferenceException

Question

在使用任务的ASP.MVC上下文中使用带有超时的ManualResetEventSlim.Wait()时，我在ASP框架中得到一个我无法捕获的NullReferenceException。

这是我的代码：

private static ManualResetEventSlim _event = new ManualResetEventSlim(false);

public async Task<ActionResult> Test()
{
    var task = Task.Factory.StartNew(() => _event.Wait(new TimeSpan(0, 0, 10)));
    await task;
    return View();
}

这是堆栈跟踪：

System.Web.dll!System.Web.ThreadContext.AssociateWithCurrentThread(bool setImpersonationContext = {unknown})
System.Web.dll!System.Web.HttpApplication.OnThreadEnterPrivate(bool setImpersonationContext = {unknown})
System.Web.dll!System.Web.HttpApplication.System.Web.Util.ISyncContext.Enter()
System.Web.dll!System.Web.Util.SynchronizationHelper.SafeWrapCallback(System.Action action = {unknown})
System.Web.dll!<>c__DisplayClass9.AnonymousMethod(System.Threading.Tasks.Task _ = {unknown})
mscorlib.dll!System.Threading.Tasks.ContinuationTaskFromTask.InnerInvoke()
mscorlib.dll!System.Threading.Tasks.Task.Execute()
mscorlib.dll!System.Threading.Tasks.Task.ExecutionContextCallback(object obj = {unknown})
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext = {unknown}, System.Threading.ContextCallback callback = {unknown}, object state = {unknown}, bool preserveSyncCtx = {unknown})
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext = {unknown}, System.Threading.ContextCallback callback = {unknown}, object state = {unknown}, bool preserveSyncCtx = {unknown})
mscorlib.dll!System.Threading.Tasks.Task.ExecuteWithThreadLocal(ref System.Threading.Tasks.Task currentTaskSlot = {unknown})
mscorlib.dll!System.Threading.Tasks.Task.ExecuteEntry(bool bPreventDoubleExecution = {unknown})
mscorlib.dll!System.Threading.Tasks.Task.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
mscorlib.dll!System.Threading.ThreadPoolWorkQueue.Dispatch()
mscorlib.dll!System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()