Allow domain config entity to be put in static cache

Can you point to the documentation for this? It looks like a change from Drupal 8.

Found this in Drupal 8.2 documentation:

https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Entity%21...

So seems a rather old feature.

Found another description here:

Boolean indicating whether entities should be statically cached during a page request.

Could give a bit of performance improvement in some cases.

Thanks! This could also apply to the DomainAlias entity definition.

I wonder how we test for this -- there have to be cases where the entity cache gets stale. Though it looks like core simply handles it for us.

See /core/tests/Drupal/KernelTests/Core/Config/ConfigEntityStaticCacheTest.php

The only possible issue here is that we often load domains very early in the bootstrap process, and the cache layer may not be present yet.

But just looking, this seems an obvious win.