@Override
    public String topic() {
        throwUnsupportedOperationExceptionIfStandby("topic");
        return super.topic();
    }
@throws StreamsException if an attempt is made to access this state store from an unknown node
@throws UnsupportedOperationException if the current streamTask type is standby
streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorContextImpl.java