docs: public StringBuilder appendItemsTo(StringBuilder buf, VectorFieldTypeInformation<BitVector> meta) {
      int it = this.iter();
      if(this.iterValid(it)) {
        while(true) {
          int v = this.iterDim(it);
          String lbl = (meta != null) ? meta.getLabel(v) : null;
          if(lbl == null) {
            buf.append(v);
          }
          else {
            buf.append(lbl);
          }
          it = this.iterAdvance(it);
          if(!this.iterValid(it)) {
            break;
          }
          buf.append(", ");
        }
      }
      return buf;
    }