Proca.Stage.UnprocessedActions (proca v3.3.1)
Stage which produces unproduced actions, which might be unprocessed because of no queue was available, or because processing failed.
We process the actions one by one synchronously because the processing will update the associated supporter.
We use thre intervals to control processing of old actions:
@time_margin - (1 minute default) - do not process actions more recent then one minute - they might be actually still processed by async-after-add processing.
@sweep_interval (1 second default) - how long to wait between processing of all history (we don't want to start from beginning straight away)