Amp\Mysql\ConnectionPool::__construct PHP Method

    public function __construct($config, $limit)
    {
        $config->ready = function ($conn) {
            $this->ready($conn);
        };
        /* @TODO ... pending queries ... */
        $config->restore = function ($conn, $init) {
            $this->unmapConnection($conn);
            if ($init && empty($this->connections)) {
                $this->virtualConnection->fail(new \Exception("Connection failed"));
            }
            return $this->getReadyConnection();
        };
        $config->busy = function ($conn) {
            if (isset($this->readyMap[$hash = spl_object_hash($conn)])) {
                unset($this->ready[$this->readyMap[$hash]]);
            }
        };
        $this->config = $config;
        $this->limit = $limit;
        $this->virtualConnection = new VirtualConnection();
        $this->addConnection();
    }