title: How to add a newline in a mapping template
body: <p>seems trivial, but I can't get it to work: I'm sending data encoded as JSON objects to API Gateway which invokes Firehose. The resulting files in S3 contain all the JSON objects in a single line. I've read that it should be possible to add newlines, but whatever I try, there is either an error or it simply doesn't do anything. The mappping template looks like this</p>
  
  <pre><code>{
      "DeliveryStreamName": "file-datadump",
      "Record": { 
      "Data": "$util.base64Encode($input.json('$'))"
      }
  }
  </code></pre>
  
  <p>Any ideas what to do?</p>