func WithAthenzURL(url string) Option {
	return func(p *pubkeyd) error {
		u := urlutil.TrimHTTPScheme(url)
		if urlutil.HasScheme(u) {
			return urlutil.ErrUnsupportedScheme
		}
		p.athenzURL = u
		return nil
	}
}
WithAthenzURL returns an AthenzURL functional option
package pubkey
import (
	"net/http"
	"time"
	"github.com/pkg/errors"
	urlutil "github.com/yahoojapan/athenz-authorizer/v5/internal/url"
)
var (
	defaultOptions = []Option{
		WithSysAuthDomain("sys.auth"),
		WithRefreshPeriod("24h"),
		WithETagExpiry("168h"),  
		WithETagPurgePeriod("84h"),
		WithRetryDelay("1m"),
		WithHTTPClient(&http.Client{}),
	}
)
type Option func(*pubkeyd) error