var _socket = new Socket(IPAddress.Any.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
_serverSocket.NoDelay = _options.NoDelay;

CancellationTokenSource connectTokenSource = new CancellationTokenSource();
connectTokenSource.CancelAfter(3000); //3秒
await _socket.ConnectAsync(RemoteEndPoint, connectTokenSource.Token);

//創(chuàng)建證書(shū)對(duì)象
var _certificate  = _certificate = new X509Certificate2(_options.PfxCertFilename, _options.PfxPassword);
 
//與客戶端進(jìn)行驗(yàn)證
if (allowingUntrustedSSLCertificate) //是否允許不受信任的證書(shū)
{
    SslStream = new SslStream(NetworkStream, false,
        (obj, certificate, chain, error) => true);
}
else
{
    SslStream = new SslStream(NetworkStream, false);
}
 
try
{
    //serverCertificate：用于對(duì)服務(wù)器進(jìn)行身份驗(yàn)證的 X509Certificate
    //clientCertificateRequired：一個(gè) Boolean 值，指定客戶端是否必須為身份驗(yàn)證提供證書(shū)
    //checkCertificateRevocation：一個(gè) Boolean 值，指定在身份驗(yàn)證過(guò)程中是否檢查證書(shū)吊銷列表
    await SslStream.AuthenticateAsServerAsync(new SslServerAuthenticationOptions()
    {
        ServerCertificate = x509Certificate,
        ClientCertificateRequired = mutuallyAuthenticate,
        CertificateRevocationCheckMode = checkCertificateRevocation ? X509RevocationMode.Online : X509RevocationMode.NoCheck
    }, cancellationToken).ConfigureAwait(false);
 
    if (!SslStream.IsEncrypted || !SslStream.IsAuthenticated)
    {
        return false;
    }
 
    if (mutuallyAuthenticate && !SslStream.IsMutuallyAuthenticated)
    {
        return false;
    }
}
catch (Exception)
{
    throw;
}
 
//完成驗(yàn)證后，通過(guò)SslStream傳輸數(shù)據(jù)
int readCount = await SslStream.ReadAsync(buffer, _lifecycleTokenSource.Token)
    .ConfigureAwait(false);

var _certificate = new X509Certificate2(_options.PfxCertFilename, _options.PfxPassword);
 
if (_options.IsSsl) //如果使用ssl加密傳輸
{
    if (_options.AllowingUntrustedSSLCertificate)//是否允許不受信任的證書(shū)
    {
        _sslStream = new SslStream(_networkStream, false,
                (obj, certificate, chain, error) => true);
    }
    else
    {
        _sslStream = new SslStream(_networkStream, false);
    }
 
    _sslStream.ReadTimeout = _options.ReadTimeout;
    _sslStream.WriteTimeout = _options.WriteTimeout;
    await _sslStream.AuthenticateAsClientAsync(new SslClientAuthenticationOptions()
    {
        TargetHost = RemoteEndPoint.Address.ToString(),
        EnabledSslProtocols = System.Security.Authentication.SslProtocols.Tls12,
        CertificateRevocationCheckMode = _options.CheckCertificateRevocation ? X509RevocationMode.Online : X509RevocationMode.NoCheck,
        ClientCertificates = new X509CertificateCollection() { _certificate }
    }, connectTokenSource.Token).ConfigureAwait(false);
 
    if (!_sslStream.IsEncrypted || !_sslStream.IsAuthenticated ||
        (_options.MutuallyAuthenticate && !_sslStream.IsMutuallyAuthenticated))
    {
        throw new InvalidOperationException("SSL authenticated faild!");
    }
}

/// <summary>
/// 開(kāi)啟Socket的KeepAlive
/// 設(shè)置tcp協(xié)議的一些KeepAlive參數(shù)
/// </summary>
/// <param name="socket"></param>
/// <param name="tcpKeepAliveInterval">沒(méi)有接收到對(duì)方確認(rèn)，繼續(xù)發(fā)送KeepAlive的發(fā)送頻率</param>
/// <param name="tcpKeepAliveTime">KeepAlive的空閑時(shí)長(zhǎng)，或者說(shuō)每次正常發(fā)送心跳的周期</param>
/// <param name="tcpKeepAliveRetryCount">KeepAlive之后設(shè)置最大允許發(fā)送?；钐綔y(cè)包的次數(shù)，到達(dá)此次數(shù)后直接放棄嘗試，并關(guān)閉連接</param>
internal static void SetKeepAlive(this Socket socket, int tcpKeepAliveInterval, int tcpKeepAliveTime, int tcpKeepAliveRetryCount)
{
    socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, true);
    socket.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.TcpKeepAliveInterval, tcpKeepAliveInterval);
    socket.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.TcpKeepAliveTime, tcpKeepAliveTime);
    socket.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.TcpKeepAliveRetryCount, tcpKeepAliveRetryCount);
}

//收到消息
 while (!_receiveDataTokenSource.Token.IsCancellationRequested)
 {
     try
     {
        //從pipe中獲取緩沖區(qū)
         Memory<byte> buffer = _pipeWriter.GetMemory(_options.BufferSize);
         int readCount = 0;
         readCount = await _sslStream.ReadAsync(buffer, _lifecycleTokenSource.Token).ConfigureAwait(false);
 
         if (readCount > 0)
         {
 
             var data = buffer.Slice(0, readCount);
             //告知消費(fèi)者，往Pipe的管道中寫(xiě)入了多少字節(jié)數(shù)據(jù)
             _pipeWriter.Advance(readCount);
         }
         else
         {
             if (IsDisconnect())
             {
                 await DisConnectAsync();
             }
 
             throw new SocketException();
         }
 
         FlushResult result = await _pipeWriter.FlushAsync().ConfigureAwait(false);
         if (result.IsCompleted)
         {
             break;
         }
     }
     catch (IOException)
     {
         //TODO log
         break;
     }
     catch (SocketException)
     {
         //TODO log
         break;
     }
     catch (TaskCanceledException)
     {
         //TODO log
         break;
     }
 }
 
 _pipeWriter.Complete();
//消費(fèi)者處理數(shù)據(jù)
 while (!_lifecycleTokenSource.Token.IsCancellationRequested)
 {
     ReadResult result = await _pipeReader.ReadAsync();
     ReadOnlySequence<byte> buffer = result.Buffer;
     ReadOnlySequence<byte> data;
     do
     {
        //通過(guò)過(guò)濾器得到一個(gè)完整的包
         data = _receivePackageFilter.ResolvePackage(ref buffer);
 
         if (!data.IsEmpty)
         {
             OnReceivedData?.Invoke(this, new ClientDataReceiveEventArgs(data.ToArray()));
         }
     }
     while (!data.IsEmpty && buffer.Length > 0);
     _pipeReader.AdvanceTo(buffer.Start);
 }
 
 _pipeReader.Complete();
/// <summary>
/// 解析數(shù)據(jù)包
/// 固定報(bào)文頭解析協(xié)議
/// </summary>
/// <param name="headerSize">數(shù)據(jù)報(bào)文頭的大小</param>
/// <param name="bodyLengthIndex">數(shù)據(jù)包大小在報(bào)文頭中的位置</param>
/// <param name="bodyLengthBytes">數(shù)據(jù)包大小在報(bào)文頭中的長(zhǎng)度</param>
/// <param name="IsLittleEndian">數(shù)據(jù)報(bào)文大小端。windows中通常是小端，unix通常是大端模式</param>
/// </summary>
/// <param name="sequence">一個(gè)完整的業(yè)務(wù)數(shù)據(jù)包</param>
public override ReadOnlySequence<byte> ResolvePackage(ref ReadOnlySequence<byte> sequence)
{
    var len = sequence.Length;
    if (len < _bodyLengthIndex) return default;
    var bodyLengthSequence = sequence.Slice(_bodyLengthIndex, _bodyLengthBytes);
    byte[] bodyLengthBytes = ArrayPool<byte>.Shared.Rent(_bodyLengthBytes);
    try
    {
        int index = 0;
        foreach (var item in bodyLengthSequence)
        {
            Array.Copy(item.ToArray(), 0, bodyLengthBytes, index, item.Length);
            index += item.Length;
        }
 
        long bodyLength = 0;
        int offset = 0;
        if (!_isLittleEndian)
        {
            offset = bodyLengthBytes.Length - 1;
            foreach (var bytes in bodyLengthBytes)
            {
                bodyLength += bytes << (offset * 8);
                offset--;
            }
        }
        else
        {
 
            foreach (var bytes in bodyLengthBytes)
            {
                bodyLength += bytes << (offset * 8);
                offset++;
            }
        }
 
        if (sequence.Length < _headerSize + bodyLength)
            return default;
 
        var endPosition = sequence.GetPosition(_headerSize + bodyLength);
        var data = sequence.Slice(0, endPosition);//得到完整數(shù)據(jù)包
        sequence = sequence.Slice(endPosition);//緩沖區(qū)中去除取到的完整包
 
        return data;
    }
    finally
    {
        ArrayPool<byte>.Shared.Return(bodyLengthBytes);
    }
}