title: PDf file on the fly-generation
body: <p>I created a pdf file based on the thymeleaf template i'm actually using the template resolver, flying saucer, to write the file on the output stream 
  but since i can't access the front in order to define the content of the recap which would be generated every now and then when the client needs to, i thought it would be better to generate the pdf file on the server side. So my question is:</p>
  
  <p><strong>Is there a way to get the output stream where my data is written and convert it in order to 
  write on the fly so it won't be created in the local storage</strong> </p>
  
  <p>Here's a part of my business logic: </p>
  
  <pre><code>os = new FileOutputStream(pdf);
  ITextRenderer renderer = new ITextRenderer();
  renderer.layout();
  renderer.createPDF(os);
  </code></pre>
  
  <p>i use this in my controller and i use attachement content attribut in the response entity </p>
  
  <p>other then that i'm open to any suggestions
  thanks in advance</p>