The methods for running things in the context of concerns have the basic pattern:
Csar.run(@Nonnull final Stream<Concern> concerns, @Nonnull final Runnable runnable)
But it might make more sense to put the Runnable first, as that's the thing being ran. I think originally the Runnable was placed last, as the runnable might be a lambda. But it's not a big deal to have the trailing concerns, and in fact the varargs version requires the concerns to be at the end:
Csar.run(@Nonnull final Runnable runnable, @Nonnull final Concern... concerns)
So making the change across the board will provide more consistency as well.
In fact we can probably remove the Csar.run(@Nonnull final Concern concern, @Nonnull final Runnable runnable) form altogether, although we should probably deprecate it, as it is shown in the current documentation.