[Improvement] add event when proxy-protocol packet is received

i see you added ConnectionInitEvent to waterfall, i would suggest an improvement
when you use Waterfall behind HAProxy, this event become quite useless as the ip the event see is the ip of the HAProxy server. So if you want to implement a connection throttler, or a macanism that prevents layer 7 flood (eg: handshake packet error flood) based on the connection IP, you can't. (not a good idea to ban your load-balancer's IP)

So, in case of proxy-protocol enabled, i think an other event should be triggered when Waterfall receive the packet from the HAProxy server with the "real connection IP". This event should allow to get the IP and to drop the associated connection (cancellable like the ConnectionInitEvent).

Thank you all for your work on this fork :)

Start by locating Waterfall's existing ConnectionInitEvent and the proxy-protocol packet handling. Determine how the real connection IP is exposed and how connection cancellation currently works; done means a cancellable event is triggered for the proxied connection and provides that IP.