@Override
  public boolean contains(Object obj) {
    if (!(obj instanceof Struct)) {
      return false;
    }
    Struct s = (Struct) obj;
    return structType.equals(StructTypeImpl.typeFromStruct(s)) && contains(s);
  }
Does this set contain specified struct?
geode-core/src/main/java/org/apache/geode/cache/query/internal/LinkedStructSet.java