toHeader method
Serialize cache-control values
Implementation
String toHeader() {
final header = <String>[];
if (maxAge != -1) header.add('$_maxAgeHeader=$maxAge');
if (maxStale != -1) header.add('$_maxStaleHeader=$maxStale');
if (minFresh != -1) header.add('$_minFreshHeader=$minFresh');
if (mustRevalidate) header.add(_mustRevalidateHeader);
if (privacy != null) header.add(privacy!);
if (noCache) header.add(_noCacheHeader);
if (noStore) header.add(_noStoreHeader);
if (other.isNotEmpty) header.addAll(other);
return header.join(', ');
}