* into a {@code String} using surrogate pairs</a>, and a {@code CharMatcher} treats these just as
 * two separate characters. {@link #countIn} counts each supplementary character as 2 {@code char}s.
 *
 * <p>For up-to-date Unicode character properties (digit, letter, etc.) and support for
 * supplementary code points, use ICU4J UCharacter and UnicodeSet (freeze() after building). For