title: SoapUI/Groovy: expand txt file, NOT re-write it
body: <p>There is no problem to save response sheet to file. Smth like</p>
  
  <pre><code>def xmlFile = "C:/.../Try.xml"
  def response = context.expand( '${Request#Response}' )
  def f = new File(xmlFile)
  f.write(response, "UTF-8")
  </code></pre>
  
  <p>BUT.</p>
  
  <p>I re-run my request in groovy script with new parameters (using while), and I need to ADD info to result file, not to re-write it. Now it's just re-writing each time:(. File created outside the cycle.</p>
  
  <p>Thanks in advance,
  Dmitry</p>