This has the downside that we need to be consistent and flush as soon as a
revision is loaded.
Otherwise, when an issue arise when loading the next revision (without a
previous flush), we could be missing data from the previous revision.
We can see that in the current implemented test. Without the flush operations,
the tests fail for example on the nixguix incremental test.
This is already covered by the current tests.
Related to T2352
Related to D2966
Note: tests will fail as the storage needs a bump