How can I see or test graceful restart in golang?

I serve http over gin's endless example or facebookgo's gracehttp example. But i want to see the difference from the basic http server.

I've sent syscall.SIGUSR1 signal with

syscall.Kill(getPid(), syscall.SIGUSR1)

The app doesn't exit, but i can not detect the restart.

Actually I have to do, init new configurations to the app when toml config file changed.