private void FillGraphemeClusterBoundaries(TinyFont font)
        {
            GlyphMetadataAppendix metadata = font.GetOrAddNewAppendix <GlyphMetadataAppendix>();

            byte[] clusterBoundaries = Resources.GraphemeBreakProperty;

            BitArray data = new BitArray(0);

            foreach (CharacterInfo info in font.EnumerateAllCharacterInfos())
            {
                byte property = FindClusterProperty(clusterBoundaries, info.Codepoint);
                data.AppendLsb(property, 4);
            }

            byte[] setData = new byte[(data.Length + 7) / 8];
            data.CopyTo(setData, 0);

            metadata.Sets.Add(setData);
            GlyphMetadataAppendix.MetadataSetOffset offset = new GlyphMetadataAppendix.MetadataSetOffset();
            offset.Id   = GlyphMetadataAppendix.GraphemeSet;
            offset.Bits = GlyphMetadataAppendix.MetadataSetBitLength.Four;

            metadata.SetsOffsets.Add(offset);
        }