Netty 4.0.21.Final 发布，此版本主要是个 bug 修复和性能提升，PooledByteBufAllocator 改进和 Recycler 改进。此版本兼容之前的 Netty 4.0.x 版本。
最重要的更新内容如下：
Epoll transport may cause StackOverflow when write many buffers via writev(...) (#2623)
Missing ensureAccessible() may cause SEGFAULT the JVM (#2622)
Could not find class 'sun.misc.Cleaner' on android (#2604)
Could not find class 'sun.nio.ch.DirectBuffer' on android (#2599)
Fix integer overflow in HttpObjectEncoder when write chunk > Integer.MAX (#2592)
Write to LITTLE_ENDIAN buffer in encoder is broken (#2587)
Inconsistent Little Endian Buffer Contents in 4.0.20.Final When Unsafe Enabled (#2580)
Optimize PoolChunk to not use DFS (#2582)
Faster Recycler implementation (#2570)
Provide a proper way to remove thread-local variables (#2578)
Netty 提供异步的、事件驱动的网络应用程序框架和工具，用以快速开发高性能、高可靠性的网络服务器和客户端程序。
在线Javadoc：http://www.ostools.net/apidocs/apidoc?api=netty
项目主页：https://github.com/netty/netty/issues?milestone=96&page=1&state=closed
下载地址：https://github.com/netty/netty
来自:开源中国社区
