title: How to write the content of a Flink var to screen in Zeppelin?
body: <p>I try to run the followin simple commands in Apache Zeppelin.</p>
  
  <pre class="lang-scala prettyprint-override"><code>%flink
  
  var rabbit = env.fromElements(
  "ARTHUR:  What, behind the rabbit?",
  "TIM:  It is the rabbit!", 
  "ARTHUR:  You silly sod!  You got us all worked up!",
  "TIM:  Well, that's no ordinary rabbit.  That's the most foul, cruel, and bad-tempered rodent you ever set eyes on.",
  "ROBIN:  You tit!  I soiled my armor I was so scared!", 
  "TIM:  Look, that rabbit's got a vicious streak a mile wide, it's a killer!")
  
  var counts = rabbit.flatMap { _.toLowerCase.split("\\W+")}.map{ (_,1)}.groupBy(0).sum(1) 
  
  counts.print()
  </code></pre>
  
  <p>I try to print out the results in the notebook. But unfortunately, I only get the following output.</p>
  
  <pre class="lang-scala prettyprint-override"><code>rabbit: org.apache.flink.api.scala.DataSet[String] = org.apache.flink.api.scala.DataSet@37fdb65c
  counts: org.apache.flink.api.scala.AggregateDataSet[(String, Int)] = org.apache.flink.api.scala.AggregateDataSet@1efc7158
  res103: org.apache.flink.api.java.operators.DataSink[(String, Int)] = DataSink '&lt;unnamed&gt;' (Print to System.out)
  </code></pre>
  
  <p>How can I spill the content of counts to the notebook in Zeppelin?</p>