docs: public boolean add(final List<LongTuple<T>> list, boolean remove_added_elements, T const_value) {
          if(list == null || list.isEmpty())
              return false;
          boolean added=false;
          // find the highest seqno (unfortunately, the list is not ordered by seqno)
          long highest_seqno=findHighestSeqno(list);
          lock.lock();
          try {
              if(highest_seqno != -1 && computeRow(highest_seqno) >= matrix.length)
                  resize(highest_seqno);
  
              for(Iterator<LongTuple<T>> it=list.iterator(); it.hasNext();) {
                  LongTuple<T> tuple=it.next();
                  long seqno=tuple.getVal1();
                  T element=const_value != null? const_value : tuple.getVal2();
                  if(_add(seqno, element, false, null))
                      added=true;
                  else if(remove_added_elements)
                      it.remove();
              }
              return added;
          }
          finally {
              lock.unlock();
          }
      }