Klever

At the moment Core always starts a specified number of such workers as parallel processes. But first these processes can be useless, e.g. when there are just a few verification tasks. Thus, I suppose to start up them lazily. Second they actually need very little computational resources which can be a reason to execute them as threads (using several CPU cores at once seems to matter always nothing) rather than as processes. BTW, similar issues exist in all places where "core.components.Component#launch_subcomponents" is invoked. Perhaps everywhere using threads instead of processes will be acceptable and will help to considerably reduce consumed computational resources.