SourceNode<?, ?> sourceNode() {
        return sourceNode;
    }
@throws StreamsException if a deserialization error occurs and the deserialization callback returns
                         {@link DeserializationExceptionHandler.DeserializationHandlerResponse#FAIL FAIL}
                         or throws an exception itself
streams/src/main/java/org/apache/kafka/streams/processor/internals/RecordDeserializer.java