getFileFromMemory() method still uses file system IO and returns a Future

## 💬 Questions and Help

Hello, I have a question - how can I access the file from in-memory storage synchronously, ideally without touching the file system IO? The `getFileFromMemory()` method returns future, and I really need the file access to be instantaneous.

首先检查 getFileFromMemory() 方法和内存中缓存的实现。确定当前设计是否支持无需文件系统 I/O 的同步访问，然后确定所需的 API 行为和测试，以明确完成这项更改意味着什么。

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