public function clearCache($site_env)
{
list($site, $env) = $this->getSiteEnv($site_env);
$workflow = $env->clearCache();
while (!$workflow->checkProgress()) {
// @TODO: Add Symfony progress bar to indicate that something is happening.
}
$this->log()->notice('Caches cleared on {site}.{env}.', ['site' => $site->get('name'), 'env' => $env->id]);
}