while (1)
{
    $read = $this->_readFds;
    $write = $this->_writeFds;
    // 等待可讀或者可寫事件
    stream_select($read, $write, $e, 0, $this->_selectTimeout);

    // 嘗試執(zhí)行定時(shí)任務(wù)
    if(!$this->_scheduler->isEmpty())
    {
        $this->tick();
    }

    // 這些描述符可讀，執(zhí)行對(duì)應(yīng)描述符的讀回調(diào)函數(shù)
    if($read)
    {
        foreach($read as $fd)
        {
            $fd_key = (int) $fd;
            if(isset($this->_allEvents))
            {
                call_user_func_array($this->_allEvents, array($this->_allEvents));
            }
        }
    }

    // 這些描述符可寫，執(zhí)行對(duì)應(yīng)描述符的寫回調(diào)函數(shù)
    if($write)
    {
        foreach($write as $fd)
        {
            $fd_key = (int) $fd;
            if(isset($this->_allEvents))
            {
                call_user_func_array($this->_allEvents, array($this->_allEvents));
            }
        }
    }
}