使用NetworkStream.BeginRead和NetworkStream.EndRead实现超时

using System;
using System.IO;
using System.Net.Sockets;
using System.Threading;

public class NetworkStreamTimeout
{
    private NetworkStream _stream;
    private byte[] _buffer;
    private int _offset;
    private int _count;
    private int _timeout;

    public NetworkStreamTimeout(NetworkStream stream, byte[] buffer, int offset, int count, int timeout)
    {
        _stream = stream;
        _buffer = buffer;
        _offset = offset;
        _count = count;
        _timeout = timeout;
    }

    public IAsyncResult BeginRead(AsyncCallback callback, object state)
    {
        var result = _stream.BeginRead(_buffer, _offset, _count, callback, state);
        ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _stream, _timeout, true);
        return result;
    }

    public int EndRead(IAsyncResult asyncResult)
    {
        return _stream.EndRead(asyncResult);
    }

    private void TimeoutCallback(object state, bool timedOut)
    {
        if (timedOut)
        {
            NetworkStream stream = (NetworkStream)state;
            stream.Close();
        }
    }
}