(PECL memcached >= 0.1.0)
Represents a connection to a set of memcached servers.
$cas_token
   , string $server_key
   , string $key
   , mixed $value
   [, int $expiration
  ] )$key
   [, int $offset = 1
   [, int $initial_value = 0
   [, int $expiry = 0
  ]]] )$server_key
   , string $key
   [, int $offset = 1
   [, int $initial_value = 0
   [, int $expiry = 0
  ]]] )$server_key
   , string $key
   [, callable $cache_cb
   [, float &$cas_token
  ]] )$server_key
   , array $keys
   [, bool $with_cas
   [, callable $value_cb
  ]] )$server_key
   , array $keys
   [, string &$cas_tokens
   [, int $flags
  ]] )$key
   [, int $offset = 1
   [, int $initial_value = 0
   [, int $expiry = 0
  ]]] )$server_key
   , string $key
   [, int $offset = 1
   [, int $initial_value = 0
   [, int $expiry = 0
  ]]] )