at least in important cases (not for non-direct action queues and some
other minor things). This version is definitely buggy, but may be tried
with success on a non-production system. I will continue to work on the
correctness, but needed to commit now to get a baseline.

things like ACL check and message parsing. This leads to a greater level
of concurrent processing. Beware, though, that this commit duplicates
some messages. May be a regression from this or an earlier commit. I will
soon sort out.

... plus some other tests, namely string generation in parallel to action
processing. The code is not yet solid and not fully compatible to
older versions. But it is good enough for an early commit and some
early testing/gaining of experience.

The optimization was done based on the fine-grained partitioning
paradigm worked on the past couple of weeks -- seems to work out
really great :)