public void EndSendAck(IAsyncResult result)
        {
            bool succeeded = false;

            try
            {
                SendAckAsyncResult.End(result);
                succeeded = true;
            }
            finally
            {
                if (!succeeded)
                {
                    this.Abort();
                }
            }
        }
            static void OnReplyCompleted(IAsyncResult result)
            {
                if (result.CompletedSynchronously)
                {
                    return;
                }

                SendAckAsyncResult thisPtr = (SendAckAsyncResult)result.AsyncState;

                Exception completionException = null;

                try
                {
                    thisPtr.OnReplyCompletedCore(result);
                }
                catch (Exception e)
                {
                    completionException = e;
                }

                thisPtr.Complete(false, completionException);
            }