public function close() {
        if (null === $this->memory) {
            return;
        }
        shm_detach($this->memory);
        $this->memory = null;
    }
public function close() {
        if (null === $this->memory) {
            return;
        }
        shm_detach($this->memory);
        $this->memory = null;
    }
Close segment
@param int