opts.go
func Sigs(sigs ...os.Signal) Option {
	return func(s *Sentinel) error {
		s.Lock()
		defer s.Unlock()

		if s.started {
			return ErrAlreadyStarted
		}

		s.shutdownSigs = sigs
		return nil
	}
}
func Sigs(sigs ...os.Signal) Option {
	return func(s *Sentinel) error {
		s.Lock()
		defer s.Unlock()

		if s.started {
			return ErrAlreadyStarted
		}

		s.shutdownSigs = sigs
		return nil
	}
}
// Sigs is a sentinel option to set the specified signals for shutdown.