Lua function for reading kerning values

[wehro]

For a LuaLaTeX package I need to read the kerning values of certain character pairs as they are defined by the current font. HarfBuzz defines a C function hb_font_get_glyph_h_kerning(). Could you please provide a Lua equivalent for this function?

[zauguin]

The function is probably not doing what you are looking for. Please consider harfbuzz/harfbuzz#2767 (comment), especially

hb_font_get_glyph_h_kerning() only queries the legacy kern table (just like FT_Get_Kerning()) and should not generally be used.