code: public final HttpServer proxyProtocol(boolean proxyProtocolEnabled) {
  		if (proxyProtocolEnabled) {
  			if (!HAProxyMessageReader.hasProxyProtocol()) {
  				throw new UnsupportedOperationException(
  				        "To enable proxyProtocol, you must add the dependency `io.netty:netty-codec-haproxy`" +
  				                " to the class path first");
  			}
  
  			return tcpConfiguration(tcpServer ->
  			        tcpServer.bootstrap(b -> BootstrapHandlers.updateConfiguration(b,
  			                NettyPipeline.ProxyProtocolDecoder,
  			                (connectionObserver, channel) -> {
  			                    channel.pipeline()
  			                           .addFirst(NettyPipeline.ProxyProtocolDecoder, new HAProxyMessageDecoder());
  			                    channel.pipeline()
  			                           .addAfter(NettyPipeline.ProxyProtocolDecoder,
  			                                     NettyPipeline.ProxyProtocolReader, new HAProxyMessageReader());
  			                })));
  		}
  		else {
  			return tcpConfiguration(tcpServer ->
  			        tcpServer.bootstrap(b -> BootstrapHandlers.removeConfiguration(b, NettyPipeline.ProxyProtocolDecoder)));
  		}
  	}
docs: Specifies whether support for the {@code "HAProxy proxy protocol"}
  for deriving information about the address of the remote peer is enabled.
  
  @param proxyProtocolEnabled if true support for the {@code "HAProxy proxy protocol"}
  for deriving information about the address of the remote peer is enabled,
  otherwise disabled.
  @return a new {@link HttpServer}