Making SocketIO (netty) thread as daemon

[chentv00]

In com.corundumstudio.socketio.SocketIOServer.class line 198 – 204, when creating NioEventLoopGroup or EpollEventLoopGroup, would it be possible to expose the 2nd parameter where we get to set the ThreadFactory? Maybe this custom ThreadFactory can be passed in via the "Configuration" object.

The reason to have a custom ThreadFactory is that by default Netty's thread creation does not set the thread as a daemon (like thread.setDaemon(true);). This can cause a non-clean shutdown like described in https://forums.couchbase.com/t/java-client-occasionally-leaks-non-daemon-netty-io-threads-after-shutdown/1252.