Including a processing instruction in docbook <programlisting> output

I would like the docbook output for program listings to look like

  <programlisting>
  <?dbfo keep-together="always" ?>
  some wonderful code
  </programlisting>

This is to prevent the listing from splitting across pages. I was hoping to use passthrough for the purpose but cannot figure out how to get the processing instruction dbfo inside the programlisting block generated for listings from within asciidoctor. Is this even possible?


/Ashok