@Override
  boolean areSerializedFieldsEqual(Filter o) {
    if (o == this) return true;
    if (!(o instanceof FilterWrapper)) return false;

    FilterWrapper other = (FilterWrapper) o;
    return this.filter.areSerializedFieldsEqual(other.filter);
  }
@param o the other filter to compare with
@return true if and only if the fields of the filter that are serialized are equal to the
        corresponding fields in other. Used for testing.
hbase-server/src/main/java/org/apache/hadoop/hbase/filter/FilterWrapper.java