title: Qt: Insert QByteArray in a file at a certain position
body: <p>Is it possible to insert a <code>QByteArray</code> on a certain position in a file?
  For example if I have a file that already has 100KB of data, is it possible to insert a <code>QByteArray</code> for example at position 20? And after that the file to be constructed of the sequence from 0KB to 20KB of data, then that <code>QByteArray</code>, and after that the sequence from 20KB to 100KB of data.</p>