Setting an EventLoopGroup in config does not work since Netty 4.2.x

[enhan]

Matching on the on the EventLoopGroup here is not correct anymore since the IOUsingEventLoopGroup did not make it to the non incubator version. At the same time (see 4.2 notes), io.netty.channel.epoll.EpollEventLoopGroup is now deprecated, as well as io.netty.channel.kqueue.KQueueEventLoopGroup .

I'd be happy to craft a PR. I'm thinking of changing the appropriate factories and to find a way to know which type of transport to instantiate (so far, I've no idea).