title: Setting http response header from AWS lambda
body: <p>My API Gateway/Lambda setup returns an HTTP response header:
  Lambda uses callback function to return the value as part of a JSON
  and the <em>Integration Response</em> maps it into a HTTP header (using <code>integration.response.body</code>)</p>
  
  <p>With this solution, the values are sent back both in the body and the header.</p>
  
  <p>How can I map headers from the Lambda response without duplicating the values in the response body?</p>