How to keep stale file around?

## 💬 Questions and Help

Hi there

I'm wanting to keep stale image files around so that, if the user is offline, the stale one is served rather than checking for a new one and then showing nothing (cause offline).

Obviously, if `maxNrOfCacheObjects` is exceeded then I would expect to see some files be removed, so this question assumes we're within the limit.

How best to achieve this?

Cheers

Tobin

No files, tests, or entry points are identified; begin by locating the cache retrieval and stale-file handling entry points in this Dart/Flutter repository. Done is not defined by the issue, so confirm whether existing configuration can serve stale files offline or whether a documented or code change is required.

Written by the indexing model from the issue text.