/**
* Flush all existing items at the server
*
* CacheMemcache::truncate() immediately invalidates all existing items.
* CacheMemcache::truncate() doesn't actually free any resources, it only marks all the items as expired,
* so occupied memory will be overwitten by new items.
*
* @return bool Returns true on success or false on failure.
*/
function truncate()
{
return $this->Memcache->flush();
}