file is downloaded by eTag condition but not updated in cache

## 🐛 Bug Report

1. Load a file image with max-age = 5 second (there is overriden value of 0 seconds with 7 days - which is not good actually).
2. Replace file on server with new one
3. Reload image

Actual result:
it is visible that code 200 is coming from file download, file is actually downloaded, but memory cache not updated, old file is added to stream produced by getFileStream(url) method (the last one, the first one is from memory cache which is OK).
App restart helps to see new file (code 304 is reported by server, file is not actually downloaded).

从 getFileStream(url) 入口点开始，跟踪服务器返回 200 响应后的路径。检查下载的文件如何更新内存缓存，然后验证替换服务器文件后重新加载是否会在不重启应用的情况下，让 stream 产生新内容。

由索引模型根据 Issue 内容生成。