@VisibleForTesting
void parseLastModifiedOrThrowException(HttpResponse from, MutableContainerPropertiesWithMetadata metadata)
throws HttpException {
String lastModified = from.getFirstHeaderOrNull(HttpHeaders.LAST_MODIFIED);
if (lastModified == null)
throw new HttpException(HttpHeaders.LAST_MODIFIED + " header not present in response: " + from);
metadata.setLastModified(dateParser.rfc822DateParse(lastModified));
if (metadata.getLastModified() == null)
throw new HttpException("could not parse: " + HttpHeaders.LAST_MODIFIED + ": " + lastModified);
}