title: What should I do when netty isWritable() return false?
body: <p>When channel is not writable, it seems that I should set AutoRead() to false to implement a backing pressure strategy, however if the app was simply producing messages without reading from channel, it doesn't help. I wonder what should I do about it, I don't want to discard my  messages, so If the Writability changed, is it a good idea to add a <code>ChannelTrafficShapingHandler</code> to the channel pipeline to reduce the qps?</p>