Accessing allObjects from DiskStorage

I've noticed an issue with the allObjects property in the DiskStorage implementation. The current default implementation returns an empty array, making it impossible to access any stored objects. Also, as of now there is no way to get allObjects from disk when they are not in memory?

The relevant code snippet from DiskStorage is as follows:

```
extension DiskStorage: StorageAware {
public var allKeys: [Key] { [] }

public var allObjects: [Value] { [] }
}
```