// Annex #29, "Unicode Text Segmentation." For each word boundary, find the
// first cased character F following the word boundary. If F exists, map F to
// Titlecase_Mapping(F); then map all characters C between F and the following
// word boundary to Lowercase_Mapping(C).
func (t *titleCaser) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {