title: Append existing PDF file
body: <p>I have some code that generates a PDF file programmatically and I need to append to it the existing file (to the end of generated one). Can somebody give an example or link?</p>
  
  <p>Thank you</p>
  
  <p>UPD#1: Actually I am looking for some piece of code of merging existing file and byte's array (of programmatically generated file)</p>