Netty客户端发起连接过程注意点

io.netty.bootstrap.Bootstrap#connect(java.net.SocketAddress)

io.netty.channel.socket.nio.NioSocketChannel#doConnect

io.netty.channel.nio.NioEventLoop#processSelectedKey(java.nio.channels.SelectionKey, io.netty.channel.nio.AbstractNioChannel)

io.netty.channel.DefaultChannelPipeline.HeadContext#channelActive

io.netty.channel.DefaultChannelPipeline.HeadContext#readIfIsAutoRead

io.netty.channel.DefaultChannelPipeline.HeadContext#read

io.netty.channel.nio.AbstractNioChannel#doBeginRead

protected void doBeginRead() throws Exception {
  final SelectionKey selectionKey = this.selectionKey;
  if (!selectionKey.isValid()) {
    return;
  }

  readPending = true;

  final int interestOps = selectionKey.interestOps();
  if ((interestOps & readInterestOp) == 0) {
    // 设置之前保存起来的事件, 例如OP_READ
    selectionKey.interestOps(interestOps | readInterestOp);
  }
}