11e6247d2a
The handler will expose built-in process and Go metrics by default, which currently duplicate some of the expvar-proxied metrics (`goroutines` vs `go_goroutines`, `memstats` vs `go_memstats`), but as long as their names are different, Prometheus server will just scrape both. This will change /debug/varz behaviour for most tsweb binaries, but notably not for control, which configures a `tsweb.VarzHandler` [explicitly](https://github.com/tailscale/corp/blob/a5b5d5167f1a2b780d313ec6a30e7b96dfa25b2d/cmd/tailcontrol/tailcontrol.go#L779) Updates https://github.com/tailscale/corp/issues/10205 Signed-off-by: Anton Tolchanov <anton@tailscale.com>