C# socket 相关问题: 为什么运行如下这段代码后，byte 的值仍然是 0?

Question

bytes = await Task.Factory.FromAsync((AsyncCallback callback, object state) =>
{
    var t= s.BeginReceive(received, received.Length, 0, SocketFlags.None, callback, state);
    return t;
}, s.EndReceive, null);