Consider using SWMR by default

[jl-wynen]

          Are we using `swmr=True` when opening the `hdf5` files in the nightly tests? We should, it will help making the file access more robust.

Originally posted by @jokasimr in #178 (comment)

[jokasimr]

I meant in the integration tests in Gitlab, because there we are reading from the ess file storage.

[jl-wynen]

I missed that part of your comment. In principle we can. But that would mean that the tests don't represent the production environment.

[jokasimr]

What is the production environment? Is that not reading files from the ess file storage in swmr mode?

[jl-wynen]

Depends on whether it is deployed in Lund or Denmark. Most likely, batch and autoreduction will be in Denmark where SWMR won't k due to AFM.

[jokasimr]

Why do you think SWMR will not work with AFM? I'm under the impression that SWMR is supposed to work even from Denmark.

Update: This has been confirmed with DST. Their intent is that reading files in SWMR mode, while they are being written, should be possible from Visa instances on the Danish side.

[YooSunYoung]

What's the conclusion here....? So we don't have to manually set swrm at all?