The services will now store a local copy of the filter lists in the worker
local data associated with the service. This removes the instance level
lock and removes the performance penalty that was previously imposed by
it.
The only remaining performance "regression" compared to 2.2 is the extra
two atomic operations per filter that a session does when it is being
created. This is quite hard to get rid of without significant amounts code
and will hopefully be just a drop in the ocean.
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