CreateMetricsListener will create a new [net.Listener] by using an known set of ports when the default address is passed with the fallback of choosing a random port when none is available.

GetMetricsKnownAddresses returns the addresses used by the metrics server to bind at startup time to allow a semi-deterministic approach to know where the server is listening at.

NewReadyServer initializes a ReadyServer and starts listening for dis/connection events.

This variable is set at compile time to allow the default local address to change.

ReadyServer serves HTTP 200 if the tunnel can serve traffic.