public OperatorSpecGraph clone() {
    if (opSpecGraphSerde == null) {
      throw new IllegalStateException("Cannot clone from an already deserialized OperatorSpecGraph.");
    }
    return opSpecGraphSerde.fromBytes(serializedOpSpecGraph);
  }
Returns a deserialized {@link OperatorSpecGraph} as a copy from this instance of {@link OperatorSpecGraph}
This is used to create per-task instance of {@link OperatorSpecGraph} when instantiating task instances.

@return a copy of this {@link OperatorSpecGraph} object via deserialization
samza-core/src/main/java/org/apache/samza/operators/OperatorSpecGraph.java