Has anyone used pango_font_get_coverage?

[AngryZealot <angryzealot gmail com>]

I realize this is more related to Pango than to GTK+, but I hope
someone can help me here.

I need to determine if a font contains a character, and PangoCoverage
does exactly what I need; eg,

PangoCoverage *coverage = pango_font_get_coverage(font, language);
PangoCoverageLevel level = pango_coverage_get(pangoCoverage, index);

My problem is that pango_font_get_coverage is leaving behind a
monstrous memory leak. Calling pango_coverage_unref appears to have no
effect. The documentation is poor, but as far as I can tell this is
the correct way to free a PangoCoverage. I am using the Windows 32-bit
binaries of the GTK+ distribution (Cairo 1.8.0, Pango 1.22.2). Has
anyone encountered this before?