Many queued files can make Zeronet stop responding?

### Step 1: Please describe your environment

* ZeroNet version: 4176
* Operating system: W10
* Web browser: FF
* Special configuration: Multiuser

### Step 2: Describe the problem:
"I made the mistake of trying to seed all small and big files on a board that apparently is mostly 0 peers. I've been stuck "updating 14000 files" for a week now and it's very unresponsive. How do I cancel trying to sync all those files?" source: [millchan](http://127.0.0.1:43110/1ADQAHsqsie5PBeQhQgjcKmUu3qdPFg6aA/?:users/12NPW6WLFBLVivNGqijcfktARobftfLFAN:dev:b79fce8b-df0d-4ab4-a89e-4c37585aa6d1#post-7f55628f-57e2-48e1-8c33-ce02eed14878)

And some time ago, i have had similar feeling, that too many (1000+) files queued and being actively downloaded (or at least attempted), maybe simultaneously on multiple zites, maybe makes zeronet do not respond other request (to load a webpage). Can this be true? If so, can you improve this so it does not influence site loading and its operations?

PS: maybe the cause of the lag/unresponding is not queued files, but the way images are loaded on the site i linked above. Because zeronet stop loading sites and when i browse opened tabs, i sometimes see that on above linked web zite is the page where many images did not loaded (instead of a image thumbnail, there is a wheel indicating image loading) and when i close that tab, zeronet start responding... i always had impression it has to do with some zite function that is made wrongly to hang. Or the function should have some timeout or something.

If the problem is the browser limit, i have following in the Firefox "about:config" page:
network.http.max-persistent-connections-per-proxy - 32
network.http.max-persistent-connections-per-server - 6
network.http.max-urgent-start-excessive-connections-per-host - 3
so i have added 0 at the end of each value in hope to remove this lag
dom.workers.maxPerDomain - 512

未指定源文件或测试。首先使用大约 14,000 个排队文件以及所描述的图像密集型 zite 重现变慢问题，然后在队列和图像请求处于活动状态时比较响应性。完成的标准是确定排队的下载、图像加载或浏览器连接限制是否导致阻塞行为，并记录具体的取消、超时或调度要求。

由索引模型根据 Issue 内容生成。