docs: protected static String print(BiConsumer<Integer,Integer> wait_strategy) {
          if(wait_strategy      == null)            return null;
          if(wait_strategy      == SPIN)            return "spin";
          else if(wait_strategy == YIELD)           return "yield";
          else if(wait_strategy == PARK)            return "park";
          else if(wait_strategy == SPIN_PARK)       return "spin-park";
          else if(wait_strategy == SPIN_YIELD)      return "spin-yield";
          else return wait_strategy.getClass().getSimpleName();
      }