/**
   * @param idx Index.
   * @return Conflict version.
   */
  @Nullable
  public GridCacheVersion conflictVersion(int idx) {
    if (conflictVers != null) {
      assert idx >= 0 && idx < conflictVers.size();

      return conflictVers.get(idx);
    }

    return null;
  }
  /**
   * @param idx Index to get.
   * @return Write value - either value, or transform closure.
   */
  public CacheObject writeValue(int idx) {
    if (vals != null) return vals.get(idx);

    return null;
  }
  /**
   * @param idx Key index.
   * @return Value.
   */
  @SuppressWarnings("unchecked")
  public CacheObject value(int idx) {
    assert op == UPDATE : op;

    return vals.get(idx);
  }