@Override
    public int hashCode() {
        return (((noCache ? 1 : 0) * 31 + (noStore ? 1 : 0)) * 31 + (noTransform ? 1 : 0)) * 31 +
               (int) (maxAgeSeconds ^ (maxAgeSeconds >>> 32));
    }
Returns a new {@link StringBuilder} with the common directives appended.
Note that the first two characters ({@code ", "} must be stripped.
core/src/main/java/com/linecorp/armeria/common/CacheControl.java