我们不时得到这个HttpListenerException： 有谁知道在什么情况下可以引发异常？
按如下方式拨打电话： 异常消息：
HttpListenerException: An operation was attempted on a nonexistent network connection
Type : System.Net.HttpListenerException, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
Message : An operation was attempted on a nonexistent network connection
Source : System
ErrorCode : 1229
NativeErrorCode: 1229
TargetSite : Boolean ReadAsyncFast(HttpListenerAsyncEventArgs)
Stack Trace : at System.Net.WebSockets.WebSocketHttpListenerDuplexStream.ReadAsyncFast(HttpListenerAsyncEventArgs eventArgs)
at System.Net.WebSockets.WebSocketHttpListenerDuplexStream.<ReadAsyncCore>d__30.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Net.WebSockets.WebSocketBase.WebSocketOperation.<Process>d__19.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Net.WebSockets.WebSocketBase.<ReceiveAsyncCore>d__45.MoveNext()
TargetSite :
Stack Trace : The stack trace is unavailable.