title: How to convert QByteArray to std::istream or std::ifstream?
body: <p>I want to create <code>istream</code> from <code>QByteArray</code> at runtime, without saving a physical file in memory of <code>QByteArray</code>.</p>
  
  <p>I found that there are many ways to do the opposite conversion, i.e. <code>istream</code> to <code>QByteArray</code>, but not this one.</p>
  
  <p>How to accomplish that?</p>