@Override
    public int hashCode() {
        return (((((super.hashCode() * 31 +
                    (cachePublic ? 1 : 0)) * 31 +
                   (cachePrivate ? 1 : 0)) * 31 +
                  (immutable ? 1 : 0)) * 31 +
                 (mustRevalidate ? 1 : 0)) * 31 +
                (proxyRevalidate ? 1 : 0)) * 31 +
               (int) (sMaxAgeSeconds ^ (sMaxAgeSeconds >>> 32));
    }
Returns a newly created {@link ServerCacheControlBuilder} which has the same initial directives with
this {@link ServerCacheControl}.
core/src/main/java/com/linecorp/armeria/common/ServerCacheControl.java