java中NIO的使用和例子
https://www.jianshu.com/p/a9d030fec081
关于Java NIO的一切
http://xintq.net/2017/06/12/everything-about-java-nio
linux io
intbuffer
https://blog.csdn.net/u010412719/article/details/52775637
fileChanel 读写文件
https://segmentfault.com/a/1190000006824107
https://www.cnblogs.com/mjorcen/p/3992371.html buffer limit postion capacity 含义
https://www.cnblogs.com/dongguacai/p/5812831.html java nio buffer解读
socketchannel write实现原理
https://juejin.im/post/5cb482a7f265da036c577d0d
深入研究Netty框架之ByteBuf功能原理及源码分析
https://my.oschina.net/7001/blog/742236
netty 零拷贝
https://segmentfault.com/a/1190000007560884
