updater

func NewUpdater(
	issuers []*issuance.Certificate,
	numShards int,
	shardWidth time.Duration,
	lookbackPeriod time.Duration,
	updatePeriod time.Duration,
	updateTimeout time.Duration,
	maxParallelism int,
	maxAttempts int,
	cacheControl string,
	expiresMargin time.Duration,
	sa sapb.StorageAuthorityClient,
	ca capb.CRLGeneratorClient,
	cs cspb.CRLStorerClient,
	stats prometheus.Registerer,
	log blog.Logger,
	clk clock.Clock,
) (*crlUpdater, error)