Rendering "in memory" using pango

[Matthew Willis <matthew willis mac com>]

I'm using pango to render text that eventually ends up in an opengl
texture.  I just need to supply opengl with a byte-array, and I have
been using the cairo backend to render to an image surface in order to
get the bytes.

Is there a way I can cut cairo out of the picture and just get the bytes
that correspond to a pango layout from pango directly?  Pango's front
page mentions this capability, but I have scoured the documentation
without finding it.  What does the front page mean by:

"Rendering can be with with Cairo or Xft libraries, or *directly to an
in-memory buffer with no additional libraries*." (emphasis mine)

Thank you for your help,
Matthew Willis