private static long parseSeconds(final String name, final String value) {
        final long delta = CacheSupport.deltaSeconds(value);
        if (delta == -1 && LOG.isDebugEnabled()) {
            LOG.debug("Directive {} is malformed: {}", name, value);
        }
        return delta;
    }
Parses the specified request header and returns a new {@link RequestCacheControl} instance containing
the relevant caching directives.

@param headerIterator the header to parse, cannot be {@code null}
@return a new {@link RequestCacheControl} instance containing the relevant caching directives parsed
from the request header
@throws IllegalArgumentException if the input header is {@code null}
httpclient5-cache/src/main/java/org/apache/hc/client5/http/impl/cache/CacheControlHeaderParser.java