docs: public static <K, V> TreeMap<K, V> sort(Map<K, V> map, Comparator<? super K> comparator) {
  		TreeMap<K, V> result;
  		if (map instanceof TreeMap) {
  			// 已经是可排序Map，此时只有比较器一致才返回原map
  			result = (TreeMap<K, V>) map;
  			if (null == comparator || comparator.equals(result.comparator())) {
  				return result;
  			}
  		} else {
  			result = newTreeMap(map, comparator);
  		}
  
  		return result;
  	}