Add proxy address information to the metrics

[violetagg]

Related to #3060

[pderop]

Apart from a few comments from javadocs, it looks okay to me.

[pderop]

I missed your last commit from df0415c, I'm rechecking ...

[pderop]

Violeta, can you please clarify the following:

Prior to the last commit (df0415c), the AbstractChannelMetricsHandler.channelRegistered method was like this:

	@Override
	public void channelRegistered(ChannelHandlerContext ctx) {
		if (!onServer) {
			ProxyHandler proxyHandler = ctx.pipeline().get(ProxyHandler.class);
			if (proxyHandler != null) {
				proxyAddress = proxyHandler.proxyAddress();
			}
                         ...

So, after the last commit, the method is now like this:

	@Override
	public void channelRegistered(ChannelHandlerContext ctx) {
		if (!onServer) {
			ChannelHandler proxyHandler = ctx.pipeline().get(NettyPipeline.ProxyHandler);
			if (proxyHandler != null) {
				proxyAddress = ((ProxyHandler) proxyHandler).proxyAddress();
			}
                 ...

Can you please tell the reason for the last commit?
Are there any cases where the ProxyHandler cannot be found using the ProxyHandler.class, like it was done prior to the last commit ?

[violetagg]

Violeta, can you please clarify the following:

Prior to the last commit (df0415c), the AbstractChannelMetricsHandler.channelRegistered method was like this:

	@Override
	public void channelRegistered(ChannelHandlerContext ctx) {
		if (!onServer) {
			ProxyHandler proxyHandler = ctx.pipeline().get(ProxyHandler.class);
			if (proxyHandler != null) {
				proxyAddress = proxyHandler.proxyAddress();
			}
                         ...

So, after the last commit, the method is now like this:

	@Override
	public void channelRegistered(ChannelHandlerContext ctx) {
		if (!onServer) {
			ChannelHandler proxyHandler = ctx.pipeline().get(NettyPipeline.ProxyHandler);
			if (proxyHandler != null) {
				proxyAddress = ((ProxyHandler) proxyHandler).proxyAddress();
			}
                 ...

Can you please tell the reason for the last commit? Are there any cases where the ProxyHandler cannot be found using the ProxyHandler.class, like it was done prior to the last commit ?

I decided that it will be better to search for the ProxyHandler added by Reactor Netty and not just for some ProxyHandler in the pipeline.

[violetagg]

@pderop Thanks for the review!