ssize_t memcached_io_flush(memcached_st *ptr, unsigned int server_key);
ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,
ssize_t memcached_io_flush(memcached_st *ptr, unsigned int server_key);
ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,