final boolean isClone(OperatorSpec other) {
    return this != other && this.getClass().isAssignableFrom(other.getClass())
        && this.opCode.equals(other.opCode) && this.opId.equals(other.opId);
  }
The set of operators that consume the messages produced from this operator.
<p>
We use a LinkedHashSet since we need both deterministic ordering in initializing/closing operators and serializability.
samza-core/src/main/java/org/apache/samza/operators/spec/OperatorSpec.java