src/Controller/Plugin/Mutex.php
protected function init($key)
    {
        if (!isset($this->files[$key])) {
            $this->files[$key] = fopen($this->dir . $key . '.lockfile', 'w+');
            $this->owns[$key] = false;
        }
    }
protected function init($key)
    {
        if (!isset($this->files[$key])) {
            $this->files[$key] = fopen($this->dir . $key . '.lockfile', 'w+');
            $this->owns[$key] = false;
        }
    }
Ceate a new resource or get exisitng with same key
@param $key