@Override
  public void setElementType(ObjectType elementType) {
    if (elementType instanceof StructType) {
      throw new IllegalArgumentException(
          "This collection does not support struct elements");
    }
    this.elementType = elementType;
  }
Empty constructor to satisfy <code>DataSerializer</code> requirements
geode-core/src/main/java/org/apache/geode/cache/query/internal/ResultsSet.java