Store Messages And Rooms

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Hello. We want to offer offline experience and we use the **MXFileStore** in the app delegate:
```objc
...
// Prepare account manager
MXKAccountManager *accountManager = [MXKAccountManager sharedManager];

// Use MXFileStore as MXStore to permanently store events.
accountManager.storeClass = [MXFileStore class];

[accountManager prepareSessionForActiveAccounts];
....

```

Then to load the recents we use this code:
```objc
// Create a data source for managing data
MXKRecentsDataSource *recentsDataSource = [[MXKRecentsDataSource alloc] initWithMatrixSession:mxSession];

// Create the view controller that will display it
MXKRecentListViewController *recentListViewController = [[MXKRecentListViewController alloc] init];
[recentListViewController displayList:recentsDataSource];
```

But without internet connection any room is shown... Why?

P.S. The session comes form the AccountManager.shared.account.first.mxSession

Start by tracing the MXFileStore setup in the app delegate and how MXKRecentsDataSource obtains rooms from the session. Reproduce the behavior with the session from AccountManager.shared.account.first.mxSession while offline, then determine why stored rooms are not displayed and verify that recents load without an internet connection.

Written by the indexing model from the issue text.