@Override
        public void process(final Record<String, String> record) {
            // making a copy of headers for safety.
            final Record<String, String> toForward = record.withHeaders(record.headers());
            toForward.headers().add(HEADER);
            context.forward(toForward);
        }
A processor that simply forwards all messages to all children with advanced timestamps.
streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorTopologyTest.java