// quorum number that can be read or write quorum depending on usage.
func reduceQuorumErrs(ctx context.Context, errs []error, ignoredErrs []error, quorum int, quorumErr error) error {
	if contextCanceled(ctx) {
		return context.Canceled
	}
	maxCount, maxErr := reduceErrs(errs, ignoredErrs)
	if maxCount >= quorum {
		return maxErr
	}
	return quorumErr
}