src/CacheStorage.php
private function getVaryKey(RequestInterface $request)
    {
        $key = $this->keyPrefix . md5('vary ' . $this->getCacheKey($request));

        return $key;
    }
private function getVaryKey(RequestInterface $request)
    {
        $key = $this->keyPrefix . md5('vary ' . $this->getCacheKey($request));

        return $key;
    }
private function getVaryKey ( RequestInterface $ request ) { $ key = $ this -> keyPrefix . md5 ( 'vary ' . $ this -> getCacheKey ( $ request ) ) ; return $ key ; }
Get the cache key for Vary headers.

@param RequestInterface $request The Request to fetch the key for.

@return string The generated key.
Get the cache key for Vary headers .