public void addProxyProtocol(ChannelPipeline pipeline) {
        pipeline.addLast(NAME, this);
    }
Decides if we need to decode a HAProxyMessage. If so, adds the decoder followed by the handler.
Else, removes itself from the pipeline.
zuul-core/src/main/java/com/netflix/netty/common/proxyprotocol/ElbProxyProtocolChannelHandler.java