title: How to know which user answered a Jenkins-Pipeline input step?
body: <p>I have a Jenkinsfile script that tests for the possibility to perform an SVN merge and then asks the user for the permission to commit the merge.</p>
  
  <p>I would like to know the username that answers the "input" step in order to write it into the commit message.</p>
  
  <p>Is this possibile?</p>
  
  <p>This is what hypothetically I would like to do:</p>
  
  <pre><code>outcome = input message: 'Merge trunk into branch?', ok: 'Merge'
  echo "User that allowed merge: ${outcome.user}"
  </code></pre>