/**
   * @param out Object output.
   * @throws IOException If failed.
   */
  @SuppressWarnings("TypeMayBeWeakened")
  private void writeFieldsCollection(ObjectOutput out) throws IOException {
    assert fields;

    out.writeInt(data != null ? data.size() : -1);

    if (data == null) return;

    for (Object o : data) {
      List<GridIndexingEntity<?>> list = (List<GridIndexingEntity<?>>) o;

      out.writeInt(list.size());

      for (GridIndexingEntity<?> idxEnt : list) {
        try {
          out.writeObject(idxEnt.value());
        } catch (GridSpiException e) {
          throw new IOException("Failed to write indexing entity: " + idxEnt, e);
        }
      }
    }
  }
 /** {@inheritDoc} */
 @Override
 public void writeExternal(ObjectOutput out) throws IOException {
   out.writeInt(cnt);
   out.writeInt(initCnt);
   out.writeBoolean(autoDel);
 }