title: Kafka wordcount not updating counts
body: <p>I'm starting experimenting Kafka Streams. I follow <a href="https://kafka.apache.org/0110/documentation/streams/quickstart" rel="nofollow noreferrer">https://kafka.apache.org/0110/documentation/streams/quickstart</a>.</p>
  
  <p>My sandbox is a box running Ubuntu 16.04.2 LTS, Kafka 0.11.0.0 and Scala 2.11.11.</p>
  
  <p>As explained in the Kafka Streams Quickstart guide, here are the steps I followed :</p>
  
  <pre><code>echo -e "all streams lead to kafka\nhello kafka streams\njoin kafka summit" &gt; file-input.txt
  
  bin/kafka-topics.sh --create \
      --zookeeper localhost:2181 \
      --replication-factor 1 \
      --partitions 1 \
      --topic streams-file-input
  
  bin/kafka-console-producer.sh --broker-list localhost:9092 --topic streams-file-input &lt; file-input.txt
  
  bin/kafka-run-class.sh org.apache.kafka.streams.examples.wordcount.WordCountDemo
  
  bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 \
      --topic streams-wordcount-output \
      --from-beginning \
      --formatter kafka.tools.DefaultMessageFormatter \
      --property print.key=true \
      --property print.value=true \
      --property key.deserializer=org.apache.kafka.common.serialization.StringDeserializer \
      --property value.deserializer=org.apache.kafka.common.serialization.LongDeserializer
  </code></pre>
  
  <p>When looking at the streams-wordcount-output by using the latter command, my standard output shows the following :</p>
  
  <pre><code>all 1
  streams 1
  lead    1
  to  1
  kafka   1
  hello   1
  kafka   2
  streams 2
  join    1
  kafka   3
  summit  1
  </code></pre>
  
  <p>Then, without interrupting the bin/kafka-console-consumer.sh command, I re-run the console producer as follow : </p>
  
  <pre><code>bin/kafka-console-producer.sh --broker-list localhost:9092 --topic streams-file-input &lt; file-input.txt
  </code></pre>
  
  <p>I'm surprised the standard output doesn't change to reflect the changes in troduced by this new addition. In my understanding, the file-input.txt was used to produce additional data, and so the word count should have refreshed (all tokens shall now be counted twice).
  What is wrong with my reasoning ?</p>