def prune
      remove_count = workers.count - living_count
      return 0 if remove_count.zero?

      logger.info "Cleaned up #{remove_count} dead workers"
      workers.delete_if { |t| !t.alive? }
      remove_count
    end
def prune
      remove_count = workers.count - living_count
      return 0 if remove_count.zero?

      logger.info "Cleaned up #{remove_count} dead workers"
      workers.delete_if { |t| !t.alive? }
      remove_count
    end
Returns [Integer] number of dead workers removed.