func AddService(f func(grpc.ServiceRegistrar) (func(), error))
AddService adds a service to the list of admin services.
NOTE: this function must only be called during initialization time (i.e. in an init() function), and is not thread-safe.
If multiple services with the same service name are added (e.g. two services for `grpc.channelz.v1.Channelz`), the server will panic on `Register()`.
func Register(s grpc.ServiceRegistrar) (cleanup func(), _ error)
Register registers the set of admin services to the given server.