code: static ArrayList<AnnounceEntry> trackers(announce_entry_vector v) {
          int size = (int) v.size();
          ArrayList<AnnounceEntry> l = new ArrayList<>(size);
  
          for (int i = 0; i < size; i++) {
              l.add(new AnnounceEntry(v.get(i)));
          }
  
          return l;
      }
docs: helper function