Acquia\Cloud\Api\CloudApiClient::purgeVarnishCache PHP Method

    public function purgeVarnishCache($site, $env, $domain)
    {
        $variables = array('site' => $site, 'env' => $env, 'domain' => $domain);
        $request = $this->delete(array('{+base_path}/sites/{site}/envs/{env}/domains/{domain}/cache.json', $variables));
        return new Response\Task($request);
    }