(PECL memcached >= 2.0.0)
Memcached::deleteMultiByKey — Delete multiple items from a specific server
   Memcached::deleteMultiByKey() is functionally equivalent to
   Memcached::deleteMulti(), except that the free-form
   server_key can be used to map the
   keys to a specific server.
  
server_keyThe key identifying the server to store the value on or retrieve it from. Instead of hashing on the actual key for the item, we hash on the server key when deciding which memcached server to talk to. This allows related items to be grouped together on a single server for efficiency with multi operations.
keysThe keys to be deleted.
timeThe amount of time the server will wait to delete the items.
Note: As of memcached 1.3.0 (released 2009) this feature is no longer supported. Passing a non-zero
timewill cause the deletion to fail. Memcached::getResultCode() will returnMEMCACHED_INVALID_ARGUMENTS.
   Returns an array indexed by keys. Each element
   is true if the corresponding key was deleted, or one of the
   Memcached::RES_* constants if the corresponding deletion
   failed.
   
   The Memcached::getResultCode() will return
   the result code for the last executed delete operation, that is, the delete
   operation for the last element of keys.
  
