def execute(*args, &task)
      if ensure_capacity?
        @scheduled_task_count += 1
        @queue << [args, task]
      else
        if @max_queue != 0 && @queue.length >= @max_queue
          handle_fallback(*args, &task)
        end
      end
      prune_pool
    end
def execute(*args, &task)
      if ensure_capacity?
        @scheduled_task_count += 1
        @queue << [args, task]
      else
        if @max_queue != 0 && @queue.length >= @max_queue
          handle_fallback(*args, &task)
        end
      end
      prune_pool
    end
A T T E N Z I O N E   A R E A   P R O T E T T A
 @!visibility private