HttpListenerResponse.Abort Method ()
Closes the connection to the client without sending a response.
Assembly: System (in System.dll)
Calling this method on an object that has already been closed has no effect. If the response has not already been closed, this method closes it and the associated HttpListenerRequest and HttpListenerContext objects. The connection to the client is also closed, regardless of the KeepAlive property value of the client request.
Available since 2.0