public HttpCacheEntry createRoot(final HttpCacheEntry latestVariant,
                                     final Collection<String> variants) {
        Args.notNull(latestVariant, "Request");
        Args.notNull(variants, "Variants");
        return new HttpCacheEntry(
                latestVariant.getRequestInstant(),
                latestVariant.getResponseInstant(),
                latestVariant.getRequestMethod(),
                latestVariant.getRequestURI(),
                headers(latestVariant.requestHeaderIterator()),
                latestVariant.getStatus(),
                headers(latestVariant.headerIterator()),
                null,
                variants);
    }
Creates a new root {@link HttpCacheEntry} (parent of multiple variants).

@param latestVariant    The most recently created variant entry
@param variants         describing cache entries that are variants of this parent entry; this
                        maps a "variant key" (derived from the varying request headers) to a
                        "cache key" (where in the cache storage the particular variant is
                        located)
httpclient5-cache/src/main/java/org/apache/hc/client5/http/cache/HttpCacheEntryFactory.java