docs: public Entry add(V value, P priority) {
          Preconditions.checkNotNull(value);
          Preconditions.checkNotNull(priority);
  
          if (size >= MAX_CAPACITY) return null;
  
          final Entry result = new Entry(value, priority);
          // add as a root
          oMinEntry = mergeLists(result, oMinEntry);
          size++;
  
          return result;
      }